复旦大学软件学院计算机系统课件 Machiine-Level Representation (X86-6 4).ppt

* * * * * * * * * * * * * * * * * * Compilers Autumn 2002 Compilers Autumn 2002 * Machine-Level Representation of Programs (x86-64) * Outline x86-64 Machine-Level Programming Procedures and Stack Alignment Byte Ordering Suggested reading Chap 3.13 IA32 Example: swap() void swap(int *xp, int *yp) { int t0 = *xp; int t1 = *yp; *xp = t1; *yp = t0; } swap: pushl %ebp movl %esp,%ebp pushl %ebx movl 12(%ebp),%ecx movl 8(%ebp),%edx movl (%ecx),%eax movl (%edx),%ebx movl %eax,(%edx) movl %ebx,(%ecx) movl -4(%ebp),%ebx movl %ebp,%esp popl %ebp ret Setup Body Finish x86-64 Example: swap() void swap(int *xp, int *yp) { int t0 = *xp; int t1 = *yp; *xp = t1; *yp = t0; } swap: movl (%rdi), %edx movl (%rsi), %eax movl %eax, (%rdi) movl %edx, (%rsi) retq Operands passed in registers First (xp) in %rdi Second (yp) in %rsi 64-bit pointers No stack operation required 32-bit data Data held in register %eax and %edx movl operation Example: swap() swap: movl (%rdi), %edx movl (%rsi), %eax movl %eax, (%rdi) movl %edx, (%rsi) retq Swap long int in 64-bit Example: swap() void swap(long int *xp, long int *yp) { long int t0 = *xp; long int t1 = *yp; *xp = t1; *yp = t0; } swap: movq (%rdi), %rdx movq (%rsi), %rax movq %rax, (%rdi) movq %rdx, (%rsi) retq 64-bit data Data held in registers %rax and %rdx movq operation “q” stands for quar-word IA32/Linux Stack Frame Caller Stack Frame Arguments for this call Return Address (pushed by “call”) Callee Stack Frame Old %ebp (saved by “push %ebp”) Saved registers Local variable s Arguments for next call * Procedures - Stack Ret Addr Arguments Old %ebp Saved registers Local variables Arguments %ebp %esp frame pointer stack pointer IA32/Linux Register Usage %eax, %edx, %ecx Caller saves prior the call if values are used by later %eax Return integer value %ebx, %esi, %edi Callee saves if want to used them %esp, %ebp special * Procedures - Register %eax %edx %ecx %ebx %esi %edi %esp %ebp Caller-Save Callee-Save Special %rbp %rsp