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| -rw-r--r-- | src/arch/x86_64.md | 62 |
1 files changed, 61 insertions, 1 deletions
diff --git a/src/arch/x86_64.md b/src/arch/x86_64.md index 7e9008d..d752b09 100644 --- a/src/arch/x86_64.md +++ b/src/arch/x86_64.md @@ -180,7 +180,7 @@ rep stosb rax 64 bit rax+rdx 128 bit ``` -- Floating point return values: +- Floating point return values ```markdown reg size ------------------- @@ -235,6 +235,64 @@ must must save these registers in case they are used. ``` > Equivalent to `leave` instruction. +## [Windows x64 ABI][winabi] +### Passing arguments to functions ([ref][winabi-args]) +> A single argument is never spread across multiple registers. +- Integer/Pointer arguments + ```markdown + reg arg + ----------- + rcx 1 + rdx 2 + r8 3 + r9 4 + ``` +- Floating point arguments + ```markdown + reg arg + ----------- + xmm0 1 + .. .. + xmm3 4 + ``` +- Additional arguments are passed on the stack. Arguments are pushed + right-to-left (RTL), meaning next arguments are closer to current `rsp`. + [See example](https://godbolt.org/z/oT5Tjdf7Y). + +### Return values from functions +- Integer/Pointer return values + ```markdown + reg size + ----------------- + rax 64 bit + ``` +- Floating point return values + ```markdown + reg size + ------------------- + xmm0 64 bit + ``` + +### Caller saved registers +Caller must save these registers if they should be preserved across function +calls. +- `rax` +- `rcx` +- `rdx` +- `r8` - `r11` +- `xmm0` - `xmm5` + +### Callee saved registers +Caller can expect these registers to be preserved across function calls. Callee +must must save these registers in case they are used. +- `rbx` +- `rbp` +- `rdi` +- `rsi` +- `rsp` +- `r12` - `r15` +- `xmm6` - `xmm15` + ## ASM skeleton Small assembler skeleton, ready to use with following properties: - use raw Linux syscalls (`man 2 syscall` for ABI) @@ -289,6 +347,8 @@ Hi ASM-World! [sysvabi]: https://www.uclibc.org/docs/psABI-x86_64.pdf +[winabi]: https://learn.microsoft.com/en-us/cpp/build/x64-software-conventions +[winabi-args]: https://learn.microsoft.com/en-us/cpp/build/x64-calling-convention [amd64_vol1]: https://www.amd.com/system/files/TechDocs/24592.pdf [amd64_vol2]: https://www.amd.com/system/files/TechDocs/24593.pdf [amd64_vol3]: https://www.amd.com/system/files/TechDocs/24594.pdf |