diff --git a/README.md b/README.md index c4572ac..19a7db7 100644 --- a/README.md +++ b/README.md @@ -14,31 +14,31 @@ ## Registers -| Register | Usage | Preserved Across Function Calls | -|------------------|-------------------------------------------------------------------------------------------|-------------------------------| -| %rax | Temporary register; with variable arguments passes information about the number of vector registers used; 1st return register | No | -| %rbx | Callee-saved register; optionally used as base pointer | Yes | -| %rcx | Used to pass 4th integer argument to functions | No | -| %rdx | Used to pass 3rd argument to functions; 2nd return register | No | -| %rsp | Stack pointer | Yes | -| %rbp | Callee-saved register; optionally used as frame pointer | Yes | -| %rsi | Used to pass 2nd argument to functions | No | -| %rdi | Used to pass 1st argument to functions | No | -| %r8 | Used to pass 5th argument to functions | No | -| %r9 | Used to pass 6th argument to functions | No | -| %r10 | Temporary register, used for passing a function’s static chain pointer | No | -| %r11 | Temporary register | No | -| %r12–%r15 | Callee-saved registers | Yes | -| %xmm0–%xmm1 | Used to pass and return floating point arguments | No | -| %xmm2–%xmm7 | Used to pass floating point arguments | No | -| %xmm8–%xmm15 | Temporary registers | No | -| %mmx0–%mmx7 | Temporary registers | No | -| %st0, %st1 | Temporary registers; used to return long double arguments | No | -| %st2–%st7 | Temporary registers | No | -| %fs | Reserved for system (as thread specific data register) | No | -| mxcsr | SSE2 control and status word | Partial | -| x87 SW | x87 status word | No | -| x87 CW | x87 control word | Yes | +| Register (32, 16, 8H, 8L)-Bit | Usage | Preserved Across Function Calls | +|--------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------|---------------------------------| +| %rax (eax, ax, ah, al) | Temporary register; with variable arguments passes information about the number of vector registers used; 1st return register | No | +| %rbx (ebx, ax, ah, al) | Callee-saved register; optionally used as base pointer | Yes | +| %rcx (ecx, cx, ch, cl) | Used to pass 4th integer argument to functions | No | +| %rdx (edx, dx, dh, dl) | Used to pass 3rd argument to functions; 2nd return register | No | +| %rsp (esp, sp, N/A, spl) | Stack pointer | Yes | +| %rbp (ebp, bp, N/A, bpl) | Callee-saved register; optionally used as frame pointer | Yes | +| %rsi (esi, si, N/A, sil) | Used to pass 2nd argument to functions | No | +| %rdi (edi, di, N/A, dil) | Used to pass 1st argument to functions | No | +| %r8 (r8d, r8w, N/A, r8b) | Used to pass 5th argument to functions | No | +| %r9 (r9d, r9w, N/A, r9b) | Used to pass 6th argument to functions | No | +| %r10 (r10d, r10w, N/A, r10b) | Temporary register, used for passing a function’s static chain pointer | No | +| %r11 (r11d, r11w, N/A, r11b) | Temporary register | No | +| %r12–%r15 (r12-15d, r12-15w, N/A, r12-15b) | Callee-saved registers | Yes | +| %xmm0–%xmm1 | Used to pass and return floating point arguments | No | +| %xmm2–%xmm7 | Used to pass floating point arguments | No | +| %xmm8–%xmm15 | Temporary registers | No | +| %mmx0–%mmx7 | Temporary registers | No | +| %st0, %st1 | Temporary registers; used to return long double arguments | No | +| %st2–%st7 | Temporary registers | No | +| %fs | Reserved for system (as thread specific data register) | No | +| mxcsr | SSE2 control and status word | Partial | +| x87 SW | x87 status word | No | +| x87 CW | x87 control word | Yes | ## Instructions