691 lines
29 KiB
C++
691 lines
29 KiB
C++
// This file is part of AsmJit project <https://asmjit.com>
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//
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// See asmjit.h or LICENSE.md for license and copyright information
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// SPDX-License-Identifier: Zlib
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#ifndef ASMJIT_X86_X86ASSEMBLER_H_INCLUDED
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#define ASMJIT_X86_X86ASSEMBLER_H_INCLUDED
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#include "../core/assembler.h"
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#include "../x86/x86emitter.h"
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#include "../x86/x86operand.h"
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ASMJIT_BEGIN_SUB_NAMESPACE(x86)
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//! \addtogroup asmjit_x86
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//! \{
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//! X86/X64 assembler implementation.
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//!
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//! x86::Assembler is a code emitter that emits machine code directly into the \ref CodeBuffer. The assembler is capable
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//! of targeting both 32-bit and 64-bit instruction sets, the instruction set can be configured through \ref CodeHolder.
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//!
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//! ### Basics
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//!
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//! The following example shows a basic use of `x86::Assembler`, how to generate a function that works in both 32-bit
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//! and 64-bit modes, and how to connect \ref JitRuntime, \ref CodeHolder, and `x86::Assembler`.
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//!
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//! ```
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//! #include <asmjit/x86.h>
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//! #include <stdio.h>
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//!
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//! using namespace asmjit;
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//!
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//! // Signature of the generated function.
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//! typedef int (*SumFunc)(const int* arr, size_t count);
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//!
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//! int main() {
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//! JitRuntime rt; // Create a runtime specialized for JIT.
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//! CodeHolder code; // Create a CodeHolder.
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//!
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//! code.init(rt.environment(), // Initialize code to match the JIT environment.
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//! rt.cpuFeatures());
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//! x86::Assembler a(&code); // Create and attach x86::Assembler to code.
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//!
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//! // Decide between 32-bit CDECL, WIN64, and SysV64 calling conventions:
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//! // 32-BIT - passed all arguments by stack.
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//! // WIN64 - passes first 4 arguments by RCX, RDX, R8, and R9.
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//! // UNIX64 - passes first 6 arguments by RDI, RSI, RCX, RDX, R8, and R9.
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//! x86::Gp arr, cnt;
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//! x86::Gp sum = x86::eax; // Use EAX as 'sum' as it's a return register.
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//!
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//! if (ASMJIT_ARCH_BITS == 64) {
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//! #if defined(_WIN32)
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//! arr = x86::rcx; // First argument (array ptr).
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//! cnt = x86::rdx; // Second argument (number of elements)
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//! #else
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//! arr = x86::rdi; // First argument (array ptr).
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//! cnt = x86::rsi; // Second argument (number of elements)
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//! #endif
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//! }
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//! else {
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//! arr = x86::edx; // Use EDX to hold the array pointer.
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//! cnt = x86::ecx; // Use ECX to hold the counter.
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//! // Fetch first and second arguments from [ESP + 4] and [ESP + 8].
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//! a.mov(arr, x86::ptr(x86::esp, 4));
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//! a.mov(cnt, x86::ptr(x86::esp, 8));
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//! }
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//!
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//! Label Loop = a.newLabel(); // To construct the loop, we need some labels.
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//! Label Exit = a.newLabel();
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//!
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//! a.xor_(sum, sum); // Clear 'sum' register (shorter than 'mov').
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//! a.test(cnt, cnt); // Border case:
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//! a.jz(Exit); // If 'cnt' is zero jump to 'Exit' now.
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//!
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//! a.bind(Loop); // Start of a loop iteration.
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//! a.add(sum, x86::dword_ptr(arr)); // Add int at [arr] to 'sum'.
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//! a.add(arr, 4); // Increment 'arr' pointer.
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//! a.dec(cnt); // Decrease 'cnt'.
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//! a.jnz(Loop); // If not zero jump to 'Loop'.
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//!
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//! a.bind(Exit); // Exit to handle the border case.
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//! a.ret(); // Return from function ('sum' == 'eax').
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//! // ----> x86::Assembler is no longer needed from here and can be destroyed <----
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//!
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//! SumFunc fn;
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//! Error err = rt.add(&fn, &code); // Add the generated code to the runtime.
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//!
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//! if (err) return 1; // Handle a possible error returned by AsmJit.
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//! // ----> CodeHolder is no longer needed from here and can be destroyed <----
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//!
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//! static const int array[6] = { 4, 8, 15, 16, 23, 42 };
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//!
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//! int result = fn(array, 6); // Execute the generated code.
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//! printf("%d\n", result); // Print sum of array (108).
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//!
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//! rt.release(fn); // Explicitly remove the function from the runtime
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//! return 0; // Everything successful...
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//! }
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//! ```
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//!
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//! The example should be self-explanatory. It shows how to work with labels, how to use operands, and how to emit
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//! instructions that can use different registers based on runtime selection. It implements 32-bit CDECL, WIN64,
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//! and SysV64 caling conventions and will work on most X86/X64 environments.
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//!
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//! Although functions prologs / epilogs can be implemented manually, AsmJit provides utilities that can be used
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//! to create function prologs and epilogs automatically, see \ref asmjit_function for more details.
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//!
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//! ### Instruction Validation
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//!
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//! Assembler prefers speed over strictness by default. The implementation checks the type of operands and fails
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//! if the signature of types is invalid, however, it does only basic checks regarding registers and their groups
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//! used in instructions. It's possible to pass operands that don't form any valid signature to the implementation
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//! and succeed. This is usually not a problem as Assembler provides typed API so operand types are normally checked
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//! by C++ compiler at compile time, however, Assembler is fully dynamic and its \ref emit() function can be called
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//! with any instruction id, options, and operands. Moreover, it's also possible to form instructions that will be
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//! accepted by the typed API, for example by calling `mov(x86::eax, x86::al)` - the C++ compiler won't see a problem
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//! as both EAX and AL are \ref Gp registers.
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//!
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//! To help with common mistakes AsmJit allows to activate instruction validation. This feature instruments
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//! the Assembler to call \ref InstAPI::validate() before it attempts to encode any instruction.
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//!
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//! The example below illustrates how validation can be turned on:
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//!
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//! ```
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//! #include <asmjit/x86.h>
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//! #include <stdio.h>
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//!
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//! using namespace asmjit;
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//!
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//! int main(int argc, char* argv[]) {
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//! JitRuntime rt; // Create a runtime specialized for JIT.
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//! CodeHolder code; // Create a CodeHolder.
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//!
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//! code.init(rt.environment(), // Initialize code to match the JIT environment.
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//! rt.cpuFeatures());
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//! x86::Assembler a(&code); // Create and attach x86::Assembler to code.
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//!
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//! // Enable strict validation.
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//! a.addDiagnosticOptions(DiagnosticOptions::kValidateAssembler);
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//!
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//! // Try to encode invalid or ill-formed instructions.
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//! Error err;
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//!
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//! // Invalid instruction.
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//! err = a.mov(x86::eax, x86::al);
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//! printf("Status: %s\n", DebugUtils::errorAsString(err));
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//!
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//! // Invalid instruction.
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//! err = a.emit(x86::Inst::kIdMovss, x86::eax, x86::xmm0);
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//! printf("Status: %s\n", DebugUtils::errorAsString(err));
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//!
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//! // Ambiguous operand size - the pointer requires size.
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//! err = a.inc(x86::ptr(x86::rax), 1);
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//! printf("Status: %s\n", DebugUtils::errorAsString(err));
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//!
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//! return 0;
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//! }
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//! ```
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//!
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//! ### Native Registers
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//!
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//! All emitters provide functions to construct machine-size registers depending on the target. This feature is
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//! for users that want to write code targeting both 32-bit and 64-bit architectures at the same time. In AsmJit
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//! terminology such registers have prefix `z`, so for example on X86 architecture the following native registers
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//! are provided:
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//!
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//! - `zax` - mapped to either `eax` or `rax`
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//! - `zbx` - mapped to either `ebx` or `rbx`
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//! - `zcx` - mapped to either `ecx` or `rcx`
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//! - `zdx` - mapped to either `edx` or `rdx`
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//! - `zsp` - mapped to either `esp` or `rsp`
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//! - `zbp` - mapped to either `ebp` or `rbp`
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//! - `zsi` - mapped to either `esi` or `rsi`
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//! - `zdi` - mapped to either `edi` or `rdi`
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//!
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//! They are accessible through \ref x86::Assembler, \ref x86::Builder, and \ref x86::Compiler. The example below
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//! illustrates how to use this feature:
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//!
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//! ```
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//! #include <asmjit/x86.h>
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//! #include <stdio.h>
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//!
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//! using namespace asmjit;
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//!
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//! typedef int (*Func)(void);
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//!
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//! int main(int argc, char* argv[]) {
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//! JitRuntime rt; // Create a runtime specialized for JIT.
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//! CodeHolder code; // Create a CodeHolder.
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//!
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//! code.init(rt.environment(), // Initialize code to match the JIT environment.
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//! rt.cpuFeatures());
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//! x86::Assembler a(&code); // Create and attach x86::Assembler to code.
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//!
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//! // Let's get these registers from x86::Assembler.
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//! x86::Gp zbp = a.zbp();
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//! x86::Gp zsp = a.zsp();
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//!
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//! int stackSize = 32;
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//!
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//! // Function prolog.
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//! a.push(zbp);
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//! a.mov(zbp, zsp);
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//! a.sub(zsp, stackSize);
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//!
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//! // ... emit some code (this just sets return value to zero) ...
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//! a.xor_(x86::eax, x86::eax);
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//!
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//! // Function epilog and return.
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//! a.mov(zsp, zbp);
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//! a.pop(zbp);
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//! a.ret();
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//!
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//! // To make the example complete let's call it.
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//! Func fn;
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//! Error err = rt.add(&fn, &code); // Add the generated code to the runtime.
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//! if (err) return 1; // Handle a possible error returned by AsmJit.
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//!
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//! int result = fn(); // Execute the generated code.
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//! printf("%d\n", result); // Print the resulting "0".
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//!
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//! rt.release(fn); // Remove the function from the runtime.
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//! return 0;
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//! }
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//! ```
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//!
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//! The example just returns `0`, but the function generated contains a standard prolog and epilog sequence and the
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//! function itself reserves 32 bytes of local stack. The advantage is clear - a single code-base can handle multiple
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//! targets easily. If you want to create a register of native size dynamically by specifying its id it's also possible:
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//!
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//! ```
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//! void example(x86::Assembler& a) {
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//! x86::Gp zax = a.gpz(x86::Gp::kIdAx);
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//! x86::Gp zbx = a.gpz(x86::Gp::kIdBx);
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//! x86::Gp zcx = a.gpz(x86::Gp::kIdCx);
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//! x86::Gp zdx = a.gpz(x86::Gp::kIdDx);
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//!
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//! // You can also change register's id easily.
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//! x86::Gp zsp = zax;
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//! zsp.setId(4); // or x86::Gp::kIdSp.
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//! }
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//! ```
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//!
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//! ### Data Embedding
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//!
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//! x86::Assembler extends the standard \ref BaseAssembler with X86/X64 specific conventions that are often used by
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//! assemblers to embed data next to the code. The following functions can be used to embed data:
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//!
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//! - \ref BaseAssembler::embedInt8() - embeds int8_t (portable naming).
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//! - \ref BaseAssembler::embedUInt8() - embeds uint8_t (portable naming).
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//! - \ref BaseAssembler::embedInt16() - embeds int16_t (portable naming).
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//! - \ref BaseAssembler::embedUInt16() - embeds uint16_t (portable naming).
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//! - \ref BaseAssembler::embedInt32() - embeds int32_t (portable naming).
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//! - \ref BaseAssembler::embedUInt32() - embeds uint32_t (portable naming).
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//! - \ref BaseAssembler::embedInt64() - embeds int64_t (portable naming).
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//! - \ref BaseAssembler::embedUInt64() - embeds uint64_t (portable naming).
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//! - \ref BaseAssembler::embedFloat() - embeds float (portable naming).
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//! - \ref BaseAssembler::embedDouble() - embeds double (portable naming).
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//!
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//! - \ref x86::Assembler::db() - embeds byte (8 bits) (x86 naming).
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//! - \ref x86::Assembler::dw() - embeds word (16 bits) (x86 naming).
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//! - \ref x86::Assembler::dd() - embeds dword (32 bits) (x86 naming).
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//! - \ref x86::Assembler::dq() - embeds qword (64 bits) (x86 naming).
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//!
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//! The following example illustrates how embed works:
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//!
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//! ```
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//! #include <asmjit/x86.h>
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//! using namespace asmjit;
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//!
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//! void embedData(x86::Assembler& a) {
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//! a.db(0xFF); // Embeds 0xFF byte.
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//! a.dw(0xFF00); // Embeds 0xFF00 word (little-endian).
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//! a.dd(0xFF000000); // Embeds 0xFF000000 dword (little-endian).
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//! a.embedFloat(0.4f); // Embeds 0.4f (32-bit float, little-endian).
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//! }
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//! ```
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//!
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//! Sometimes it's required to read the data that is embedded after code, for example. This can be done through
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//! \ref Label as shown below:
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//!
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//! ```
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//! #include <asmjit/x86.h>
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//! using namespace asmjit;
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//!
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//! void embedData(x86::Assembler& a, const Label& L_Data) {
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//! x86::Gp addr = a.zax(); // EAX or RAX.
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//! x86::Gp val = x86::edi; // Where to store some value...
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//!
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//! // Approach 1 - Load the address to register through LEA. This approach
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//! // is flexible as the address can be then manipulated, for
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//! // example if you have a data array, which would need index.
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//! a.lea(addr, L_Data); // Loads the address of the label to EAX or RAX.
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//! a.mov(val, dword_ptr(addr));
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//!
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//! // Approach 2 - Load the data directly by using L_Data in address. It's
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//! // worth noting that this doesn't work with indexes in X64
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//! // mode. It will use absolute address in 32-bit mode and
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//! // relative address (RIP) in 64-bit mode.
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//! a.mov(val, dword_ptr(L_Data));
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//! }
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//! ```
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//!
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//! ### Label Embedding
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//!
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//! It's also possible to embed labels. In general AsmJit provides the following options:
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//!
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//! - \ref BaseEmitter::embedLabel() - Embeds absolute address of a label. This is target dependent and would
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//! embed either 32-bit or 64-bit data that embeds absolute label address. This kind of embedding cannot be
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//! used in a position independent code.
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//!
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//! - \ref BaseEmitter::embedLabelDelta() - Embeds a difference between two labels. The size of the difference
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//! can be specified so it's possible to embed 8-bit, 16-bit, 32-bit, and 64-bit difference, which is sufficient
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//! for most purposes.
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//!
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//! The following example demonstrates how to embed labels and their differences:
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//!
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//! ```
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//! #include <asmjit/x86.h>
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//! using namespace asmjit;
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//!
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//! void embedLabel(x86::Assembler& a, const Label& L_Data) {
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//! // [1] Embed L_Data - the size of the data will be dependent on the target.
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//! a.embedLabel(L_Data);
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//!
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//! // [2] Embed a 32-bit difference of two labels.
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//! Label L_Here = a.newLabel();
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//! a.bind(L_Here);
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//! // Embeds int32_t(L_Data - L_Here).
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//! a.embedLabelDelta(L_Data, L_Here, 4);
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//! }
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//! ```
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//!
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//! ### Using FuncFrame and FuncDetail with x86::Assembler
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//!
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//! The example below demonstrates how \ref FuncFrame and \ref FuncDetail can be used together with \ref x86::Assembler
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//! to generate a function that will use platform dependent calling conventions automatically depending on the target:
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//!
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//! ```
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//! #include <asmjit/x86.h>
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//! #include <stdio.h>
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//!
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//! using namespace asmjit;
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//!
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//! typedef void (*SumIntsFunc)(int* dst, const int* a, const int* b);
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//!
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//! int main(int argc, char* argv[]) {
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//! JitRuntime rt; // Create JIT Runtime.
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//! CodeHolder code; // Create a CodeHolder.
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//!
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//! code.init(rt.environment(), // Initialize code to match the JIT environment.
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//! rt.cpuFeatures());
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//! x86::Assembler a(&code); // Create and attach x86::Assembler to code.
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//!
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//! // Decide which registers will be mapped to function arguments. Try changing
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//! // registers of dst, src_a, and src_b and see what happens in function's
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//! // prolog and epilog.
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//! x86::Gp dst = a.zax();
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//! x86::Gp src_a = a.zcx();
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//! x86::Gp src_b = a.zdx();
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//!
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//! X86::Xmm vec0 = x86::xmm0;
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//! X86::Xmm vec1 = x86::xmm1;
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//!
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//! // Create/initialize FuncDetail and FuncFrame.
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//! FuncDetail func;
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//! func.init(FuncSignatureT<void, int*, const int*, const int*>(CallConvId::kHost));
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//!
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//! FuncFrame frame;
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//! frame.init(func);
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//!
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//! // Make XMM0 and XMM1 dirty - RegGroup::kVec describes XMM|YMM|ZMM registers.
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//! frame.setDirtyRegs(RegGroup::kVec, IntUtils::mask(0, 1));
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//!
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//! // Alternatively, if you don't want to use register masks you can pass BaseReg
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//! // to addDirtyRegs(). The following code would add both xmm0 and xmm1.
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//! frame.addDirtyRegs(x86::xmm0, x86::xmm1);
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//!
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//! FuncArgsAssignment args(&func); // Create arguments assignment context.
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//! args.assignAll(dst, src_a, src_b);// Assign our registers to arguments.
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//! args.updateFrameInfo(frame); // Reflect our args in FuncFrame.
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//! frame.finalize(); // Finalize the FuncFrame (updates it).
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//!
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//! a.emitProlog(frame); // Emit function prolog.
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//! a.emitArgsAssignment(frame, args);// Assign arguments to registers.
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//! a.movdqu(vec0, x86::ptr(src_a)); // Load 4 ints from [src_a] to XMM0.
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//! a.movdqu(vec1, x86::ptr(src_b)); // Load 4 ints from [src_b] to XMM1.
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//! a.paddd(vec0, vec1); // Add 4 ints in XMM1 to XMM0.
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//! a.movdqu(x86::ptr(dst), vec0); // Store the result to [dst].
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//! a.emitEpilog(frame); // Emit function epilog and return.
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//!
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//! SumIntsFunc fn;
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//! Error err = rt.add(&fn, &code); // Add the generated code to the runtime.
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//! if (err) return 1; // Handle a possible error case.
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//!
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//! // Execute the generated function.
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//! int inA[4] = { 4, 3, 2, 1 };
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//! int inB[4] = { 1, 5, 2, 8 };
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//! int out[4];
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//! fn(out, inA, inB);
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//!
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//! // Prints {5 8 4 9}
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//! printf("{%d %d %d %d}\n", out[0], out[1], out[2], out[3]);
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//!
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//! rt.release(fn);
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//! return 0;
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//! }
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//! ```
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//!
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//! ### Using x86::Assembler as Code-Patcher
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//!
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//! This is an advanced topic that is sometimes unavoidable. AsmJit by default appends machine code it generates
|
|
//! into a \ref CodeBuffer, however, it also allows to set the offset in \ref CodeBuffer explicitly and to overwrite
|
|
//! its content. This technique is extremely dangerous as X86 instructions have variable length (see below), so you
|
|
//! should in general only patch code to change instruction's immediate values or some other details not known the
|
|
//! at a time the instruction was emitted. A typical scenario that requires code-patching is when you start emitting
|
|
//! function and you don't know how much stack you want to reserve for it.
|
|
//!
|
|
//! Before we go further it's important to introduce instruction options, because they can help with code-patching
|
|
//! (and not only patching, but that will be explained in AVX-512 section):
|
|
//!
|
|
//! - Many general-purpose instructions (especially arithmetic ones) on X86 have multiple encodings - in AsmJit
|
|
//! this is usually called 'short form' and 'long form'.
|
|
//!
|
|
//! - AsmJit always tries to use 'short form' as it makes the resulting machine-code smaller, which is always
|
|
//! good - this decision is used by majority of assemblers out there.
|
|
//!
|
|
//! - AsmJit allows to override the default decision by using `short_()` and `long_()` instruction options to force
|
|
//! short or long form, respectively. The most useful is `long_()` as it basically forces AsmJit to always emit
|
|
//! the longest form. The `short_()` is not that useful as it's automatic (except jumps to non-bound labels). Note
|
|
//! that the underscore after each function name avoids collision with built-in C++ types.
|
|
//!
|
|
//! To illustrate what short form and long form means in binary let's assume we want to emit "add esp, 16" instruction,
|
|
//! which has two possible binary encodings:
|
|
//!
|
|
//! - `83C410` - This is a short form aka `short add esp, 16` - You can see opcode byte (0x8C), MOD/RM byte (0xC4)
|
|
//! and an 8-bit immediate value representing `16`.
|
|
//!
|
|
//! - `81C410000000` - This is a long form aka `long add esp, 16` - You can see a different opcode byte (0x81), the
|
|
//! same Mod/RM byte (0xC4) and a 32-bit immediate in little-endian representing `16`.
|
|
//!
|
|
//! It should be obvious that patching an existing instruction into an instruction having a different size may create
|
|
//! various problems. So it's recommended to be careful and to only patch instructions into instructions having the
|
|
//! same size. The example below demonstrates how instruction options can be used to guarantee the size of an
|
|
//! instruction by forcing the assembler to use long-form encoding:
|
|
//!
|
|
//! ```
|
|
//! #include <asmjit/x86.h>
|
|
//! #include <stdio.h>
|
|
//!
|
|
//! using namespace asmjit;
|
|
//!
|
|
//! typedef int (*Func)(void);
|
|
//!
|
|
//! int main(int argc, char* argv[]) {
|
|
//! JitRuntime rt; // Create a runtime specialized for JIT.
|
|
//! CodeHolder code; // Create a CodeHolder.
|
|
//!
|
|
//! code.init(rt.environment(), // Initialize code to match the JIT environment.
|
|
//! rt.cpuFeatures());
|
|
//! x86::Assembler a(&code); // Create and attach x86::Assembler to code.
|
|
//!
|
|
//! // Let's get these registers from x86::Assembler.
|
|
//! x86::Gp zbp = a.zbp();
|
|
//! x86::Gp zsp = a.zsp();
|
|
//!
|
|
//! // Function prolog.
|
|
//! a.push(zbp);
|
|
//! a.mov(zbp, zsp);
|
|
//!
|
|
//! // This is where we are gonna patch the code later, so let's get the offset
|
|
//! // (the current location) from the beginning of the code-buffer.
|
|
//! size_t patchOffset = a.offset();
|
|
//! // Let's just emit 'sub zsp, 0' for now, but don't forget to use LONG form.
|
|
//! a.long_().sub(zsp, 0);
|
|
//!
|
|
//! // ... emit some code (this just sets return value to zero) ...
|
|
//! a.xor_(x86::eax, x86::eax);
|
|
//!
|
|
//! // Function epilog and return.
|
|
//! a.mov(zsp, zbp);
|
|
//! a.pop(zbp);
|
|
//! a.ret();
|
|
//!
|
|
//! // Now we know how much stack size we want to reserve. I have chosen 128
|
|
//! // bytes on purpose as it's encodable only in long form that we have used.
|
|
//!
|
|
//! int stackSize = 128; // Number of bytes to reserve on the stack.
|
|
//! a.setOffset(patchOffset); // Move the current cursor to `patchOffset`.
|
|
//! a.long_().sub(zsp, stackSize); // Patch the code; don't forget to use LONG form.
|
|
//!
|
|
//! // Now the code is ready to be called
|
|
//! Func fn;
|
|
//! Error err = rt.add(&fn, &code); // Add the generated code to the runtime.
|
|
//! if (err) return 1; // Handle a possible error returned by AsmJit.
|
|
//!
|
|
//! int result = fn(); // Execute the generated code.
|
|
//! printf("%d\n", result); // Print the resulting "0".
|
|
//!
|
|
//! rt.release(fn); // Remove the function from the runtime.
|
|
//! return 0;
|
|
//! }
|
|
//! ```
|
|
//!
|
|
//! If you run the example it will just work, because both instructions have the same size. As an experiment you can
|
|
//! try removing `long_()` form to see what happens when wrong code is generated.
|
|
//!
|
|
//! ### Code Patching and REX Prefix
|
|
//!
|
|
//! In 64-bit mode there is one more thing to worry about when patching code: REX prefix. It's a single byte prefix
|
|
//! designed to address registers with ids from 9 to 15 and to override the default width of operation from 32 to 64
|
|
//! bits. AsmJit, like other assemblers, only emits REX prefix when it's necessary. If the patched code only changes
|
|
//! the immediate value as shown in the previous example then there is nothing to worry about as it doesn't change
|
|
//! the logic behind emitting REX prefix, however, if the patched code changes register id or overrides the operation
|
|
//! width then it's important to take care of REX prefix as well.
|
|
//!
|
|
//! AsmJit contains another instruction option that controls (forces) REX prefix - `rex()`. If you use it the
|
|
//! instruction emitted will always use REX prefix even when it's encodable without it. The following list contains
|
|
//! some instructions and their binary representations to illustrate when it's emitted:
|
|
//!
|
|
//! - `__83C410` - `add esp, 16` - 32-bit operation in 64-bit mode doesn't require REX prefix.
|
|
//! - `4083C410` - `rex add esp, 16` - 32-bit operation in 64-bit mode with forced REX prefix (0x40).
|
|
//! - `4883C410` - `add rsp, 16` - 64-bit operation in 64-bit mode requires REX prefix (0x48).
|
|
//! - `4183C410` - `add r12d, 16` - 32-bit operation in 64-bit mode using R12D requires REX prefix (0x41).
|
|
//! - `4983C410` - `add r12, 16` - 64-bit operation in 64-bit mode using R12 requires REX prefix (0x49).
|
|
//!
|
|
//! ### More Prefixes
|
|
//!
|
|
//! X86 architecture is known for its prefixes. AsmJit supports all prefixes
|
|
//! that can affect how the instruction is encoded:
|
|
//!
|
|
//! ```
|
|
//! #include <asmjit/x86.h>
|
|
//!
|
|
//! using namespace asmjit;
|
|
//!
|
|
//! void prefixesExample(x86::Assembler& a) {
|
|
//! // Lock prefix for implementing atomics:
|
|
//! // lock add dword ptr [dst], 1
|
|
//! a.lock().add(x86::dword_ptr(dst), 1);
|
|
//!
|
|
//! // Similarly, XAcquire/XRelease prefixes are also available:
|
|
//! // xacquire add dword ptr [dst], 1
|
|
//! a.xacquire().add(x86::dword_ptr(dst), 1);
|
|
//!
|
|
//! // Rep prefix (see also repe/repz and repne/repnz):
|
|
//! // rep movs byte ptr [dst], byte ptr [src]
|
|
//! a.rep().movs(x86::byte_ptr(dst), x86::byte_ptr(src));
|
|
//!
|
|
//! // Forcing REX prefix in 64-bit mode.
|
|
//! // rex mov eax, 1
|
|
//! a.rex().mov(x86::eax, 1);
|
|
//!
|
|
//! // AVX instruction without forced prefix uses the shortest encoding:
|
|
//! // vaddpd xmm0, xmm1, xmm2 -> [C5|F1|58|C2]
|
|
//! a.vaddpd(x86::xmm0, x86::xmm1, x86::xmm2);
|
|
//!
|
|
//! // Forcing VEX3 prefix (AVX):
|
|
//! // vex3 vaddpd xmm0, xmm1, xmm2 -> [C4|E1|71|58|C2]
|
|
//! a.vex3().vaddpd(x86::xmm0, x86::xmm1, x86::xmm2);
|
|
//!
|
|
//! // Forcing EVEX prefix (AVX512):
|
|
//! // evex vaddpd xmm0, xmm1, xmm2 -> [62|F1|F5|08|58|C2]
|
|
//! a.evex().vaddpd(x86::xmm0, x86::xmm1, x86::xmm2);
|
|
//!
|
|
//! // Some instructions accept prefixes not originally intended to:
|
|
//! // rep ret
|
|
//! a.rep().ret();
|
|
//! }
|
|
//! ```
|
|
//!
|
|
//! It's important to understand that prefixes are part of instruction options. When a member function that involves
|
|
//! adding a prefix is called the prefix is combined with existing instruction options, which will affect the next
|
|
//! instruction generated.
|
|
//!
|
|
//! ### Generating AVX512 code.
|
|
//!
|
|
//! x86::Assembler can generate AVX512+ code including the use of opmask registers. Opmask can be specified through
|
|
//! \ref x86::Assembler::k() function, which stores it as an extra register, which will be used by the next
|
|
//! instruction. AsmJit uses such concept for manipulating instruction options as well.
|
|
//!
|
|
//! The following AVX512 features are supported:
|
|
//!
|
|
//! - Opmask selector {k} and zeroing {z}.
|
|
//! - Rounding modes {rn|rd|ru|rz} and suppress-all-exceptions {sae} option.
|
|
//! - AVX512 broadcasts {1toN}.
|
|
//!
|
|
//! The following example demonstrates how AVX512 features can be used:
|
|
//!
|
|
//! ```
|
|
//! #include <asmjit/x86.h>
|
|
//!
|
|
//! using namespace asmjit;
|
|
//!
|
|
//! void generateAVX512Code(x86::Assembler& a) {
|
|
//! using namespace x86;
|
|
//!
|
|
//! // Opmask Selectors
|
|
//! // ----------------
|
|
//! //
|
|
//! // - Opmask / zeroing is part of the instruction options / extraReg.
|
|
//! // - k(reg) is like {kreg} in Intel syntax.
|
|
//! // - z() is like {z} in Intel syntax.
|
|
//!
|
|
//! // vaddpd zmm {k1} {z}, zmm1, zmm2
|
|
//! a.k(k1).z().vaddpd(zmm0, zmm1, zmm2);
|
|
//!
|
|
//! // Memory Broadcasts
|
|
//! // -----------------
|
|
//! //
|
|
//! // - Broadcast data is part of memory operand.
|
|
//! // - Use x86::Mem::_1toN(), which returns a new x86::Mem operand.
|
|
//!
|
|
//! // vaddpd zmm0 {k1} {z}, zmm1, [rcx] {1to8}
|
|
//! a.k(k1).z().vaddpd(zmm0, zmm1, x86::mem(rcx)._1to8());
|
|
//!
|
|
//! // Embedded Rounding & Suppress-All-Exceptoins
|
|
//! // -------------------------------------------
|
|
//! //
|
|
//! // - Rounding mode and {sae} are part of instruction options.
|
|
//! // - Use sae() to enable exception suppression.
|
|
//! // - Use rn_sae(), rd_sae(), ru_sae(), and rz_sae() - to enable rounding.
|
|
//! // - Embedded rounding implicitly sets {sae} as well, that's why the API
|
|
//! // also has sae() suffix, to make it clear.
|
|
//!
|
|
//! // vcmppd k1, zmm1, zmm2, 0x00 {sae}
|
|
//! a.sae().vcmppd(k1, zmm1, zmm2, 0);
|
|
//!
|
|
//! // vaddpd zmm0, zmm1, zmm2 {rz}
|
|
//! a.rz_sae().vaddpd(zmm0, zmm1, zmm2);
|
|
//! }
|
|
//! ```
|
|
class ASMJIT_VIRTAPI Assembler
|
|
: public BaseAssembler,
|
|
public EmitterImplicitT<Assembler> {
|
|
public:
|
|
ASMJIT_NONCOPYABLE(Assembler)
|
|
typedef BaseAssembler Base;
|
|
|
|
//! \name Construction & Destruction
|
|
//! \{
|
|
|
|
ASMJIT_API explicit Assembler(CodeHolder* code = nullptr) noexcept;
|
|
ASMJIT_API virtual ~Assembler() noexcept;
|
|
|
|
//! \}
|
|
|
|
//! \cond INTERNAL
|
|
//! \name Internal
|
|
//! \{
|
|
|
|
// NOTE: x86::Assembler uses _privateData to store 'address-override' bit that is used to decide whether to emit
|
|
// address-override (67H) prefix based on the memory BASE+INDEX registers. It's either `kX86MemInfo_67H_X86` or
|
|
// `kX86MemInfo_67H_X64`.
|
|
inline uint32_t _addressOverrideMask() const noexcept { return _privateData; }
|
|
inline void _setAddressOverrideMask(uint32_t m) noexcept { _privateData = m; }
|
|
|
|
//! \}
|
|
//! \endcond
|
|
|
|
//! \name Emit
|
|
//! \{
|
|
|
|
ASMJIT_API Error _emit(InstId instId, const Operand_& o0, const Operand_& o1, const Operand_& o2, const Operand_* opExt) override;
|
|
|
|
//! \}
|
|
//! \endcond
|
|
|
|
//! \name Align
|
|
//! \{
|
|
|
|
ASMJIT_API Error align(AlignMode alignMode, uint32_t alignment) override;
|
|
|
|
//! \}
|
|
|
|
//! \name Events
|
|
//! \{
|
|
|
|
ASMJIT_API Error onAttach(CodeHolder* code) noexcept override;
|
|
ASMJIT_API Error onDetach(CodeHolder* code) noexcept override;
|
|
|
|
//! \}
|
|
};
|
|
|
|
//! \}
|
|
|
|
ASMJIT_END_SUB_NAMESPACE
|
|
|
|
#endif // ASMJIT_X86_X86ASSEMBLER_H_INCLUDED
|