X86-64 Reference Sheet

X86-64 Reference Sheet I

https://www.cs.cmu.edu/afs/cs/academic/class/15213-s20/www/recitations/x86-cheat-sheet.pdf

X86-64 Reference Sheet II

Registers

Register	Purpose	Saved across calls
%rax	temp register; return value	No
%rbx	callee-saved	Yes
%rcx	used to pass 4th argument to functions	No
%rdx	used to pass 3rd argument to functions	No
%rsp	stack pointer	Yes
%rbp	callee-saved; base 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-r11	temporary	No
%r12-r15	callee-saved registers	Yes

Stack Organization

Position	Contents	Frame
8n+16(%rbp)	argument n	Previous
...	...
16(%rbp)	argument 7
8(%rbp)	return address	Current
0(%rbp)	previous %rbp value
-8(%rbp)	locals and temps
...
0(%rsp)

Prologue: 

// call -> pushs %rip onto stack
push %ebp
mov %esp, %ebp

Epilogue：

mov %ebp, %esp
pop %ebp
// ret -> pops %rip from stack

 

SIMD: MMX, SSE, AVX

512-bit	256-bit	128-bit	Preserved	Usage
zmm0	ymm0	xmm0		arg1, return
zmm1	ymm1	xmm1		arg2
⋮				⋮
zmm7	ymm7	xmm7		arg8
zmm8	ymm8	xmm8
⋮
zmm15	ymm15	xmm15

Example:

double foo(double x, int y) {
  return x + (double) y;
}

_Z3foodi:
	cvtsi2sd	%edi, %xmm1
	addsd	%xmm1, %xmm0
	ret