#include <stdio.h>
const char * month[] = {
"January",
"February",
"March",
"April",
"May",
"June",
"July",
"August",
"September",
"October",
"November",
"December"
};
const char * get_month(int m)
{
return month[m];
}
void main()
{
printf("month=%s\n", get_month(9)); // month=October
}
#if 0
/*
* intel
*/
0000000000001149 <get_month>:
1149: f3 0f 1e fa endbr64
114d: 55 push %rbp
114e: 48 89 e5 mov %rsp,%rbp
1151: 89 7d fc mov %edi,-0x4(%rbp)
1154: 8b 45 fc mov -0x4(%rbp),%eax
1157: 48 98 cltq
1159: 48 8d 14 c5 00 00 00 lea 0x0(,%rax,8),%rdx // rdx=rax*8+0--> 9*8, 因是64bit，所以是8.
1160: 00
1161: 48 8d 05 b8 2e 00 00 lea 0x2eb8(%rip),%rax # 4020 <month> // 指向数据区
1168: 48 8b 04 02 mov (%rdx,%rax,1),%rax
116c: 5d pop %rbp
116d: c3 retq
000000000000116e <main>:
116e: f3 0f 1e fa endbr64
1172: 55 push %rbp
1173: 48 89 e5 mov %rsp,%rbp
1176: bf 09 00 00 00 mov $0x9,%edi
117b: e8 c9 ff ff ff callq 1149 <get_month>
1180: 48 89 c6 mov %rax,%rsi
1183: 48 8d 3d d0 0e 00 00 lea 0xed0(%rip),%rdi # 205a <_IO_stdin_used+0x5a>
118a: b8 00 00 00 00 mov $0x0,%eax
118f: e8 bc fe ff ff callq 1050 <printf@plt>
1194: 90 nop
1195: 5d pop %rbp
1196: c3 retq
1197: 66 0f 1f 84 00 00 00 nopw 0x0(%rax,%rax,1)
119e: 00 00
/*
* arm
*/
000000000040055c <get_month>:
40055c: d10043ff sub sp, sp, #0x10
400560: b9000fe0 str w0, [sp, #12]
400564: b0000080 adrp x0, 411000 <__libc_start_main@GLIBC_2.17>
400568: 9100c000 add x0, x0, #0x30 // 指向数据区
40056c: b9800fe1 ldrsw x1, [sp, #12]
400570: f8617800 ldr x0, [x0, x1, lsl #3]
400574: 910043ff add sp, sp, #0x10
400578: d65f03c0 ret
000000000040057c <main>:
40057c: a9bf7bfd stp x29, x30, [sp, #-16]!
400580: 910003fd mov x29, sp
400584: 52800120 mov w0, #0x9 // #9
400588: 97fffff5 bl 40055c <get_month>
40058c: aa0003e1 mov x1, x0
400590: 90000000 adrp x0, 400000 <_init-0x3e8>
400594: 911b6000 add x0, x0, #0x6d8
400598: 97ffffae bl 400450 <printf@plt>
40059c: d503201f nop
4005a0: a8c17bfd ldp x29, x30, [sp], #16
4005a4: d65f03c0 ret
#endif