#include <stdio.h>
int switch1(int a, int b, int i){
switch (i){
case 1:
return a + b;
break;
case 2:
return a - b;
break;
case 3:
return a * b;
break;
case 4:
return a / b;
break;
default:
return a + b;
break;
}
}
int main(int argc, char* argv[]){
printf("switch1:%d\n", switch1(3, 5, 3));
return 0;
}
.text:000085A0 ; =============== S U B R O U T I N E =======================================
.text:000085A0
.text:000085A0
.text:000085A0
.text:000085A0 switch1 ; CODE XREF: main+10↓p
.text:000085A0 ; __unwind {
.text:000085A0 SUB R2, R2, #1 ; arg2 = arg2 - 1
.text:000085A4 PUSH {R4,LR} ; 栈上保存R4 和 LR 的值,当前LR是外层调用函数调用处下一行的地址
.text:000085A8 MOV R3, R0 ; a = arg0
.text:000085AC CMP R2, #3 ; switch 4 cases
.text:000085B0 ADDLS PC, PC, R2,LSL#2 ; switch jump (if R2 <=3 则 PC = PC + R2*4)
.text:000085B4 ; ---------------------------------------------------------------------------
.text:000085B4
.text:000085B4 loc_85B4 ; CODE XREF: switch1+10↑j
.text:000085B4 B def_85B0 ; jumptable 000085B0 default case
.text:000085B8 ; ---------------------------------------------------------------------------
.text:000085B8
.text:000085B8 loc_85B8 ; CODE XREF: switch1+10↑j
.text:000085B8 B loc_85E0 ; jumptable 000085B0 case 0
.text:000085BC ; ---------------------------------------------------------------------------
.text:000085BC
.text:000085BC loc_85BC ; CODE XREF: switch1+10↑j
.text:000085BC B loc_85D8 ; jumptable 000085B0 case 1
.text:000085C0 ; ---------------------------------------------------------------------------
.text:000085C0
.text:000085C0 loc_85C0 ; CODE XREF: switch1+10↑j
.text:000085C0 B loc_85D0 ; jumptable 000085B0 case 2
.text:000085C4 ; ---------------------------------------------------------------------------
.text:000085C4
.text:000085C4 loc_85C4 ; CODE XREF: switch1+10↑j
.text:000085C4 B loc_85C8 ; jumptable 000085B0 case 3
.text:000085C8 ; ---------------------------------------------------------------------------
.text:000085C8
.text:000085C8 loc_85C8 ; CODE XREF: switch1+10↑j
.text:000085C8 ; switch1:loc_85C4↑j
.text:000085C8 BL sub_8620 ; jumptable 000085B0 case 3
.text:000085CC POP {R4,PC} ; 弹出栈上的值,其中LR的值直接赋给了PC,实现出函数
.text:000085D0 ; ---------------------------------------------------------------------------
.text:000085D0
.text:000085D0 loc_85D0 ; CODE XREF: switch1+10↑j
.text:000085D0 ; switch1:loc_85C0↑j
.text:000085D0 MUL R0, R3, R1 ; jumptable 000085B0 case 2
.text:000085D4 POP {R4,PC}
.text:000085D8 ; ---------------------------------------------------------------------------
.text:000085D8
.text:000085D8 loc_85D8 ; CODE XREF: switch1+10↑j
.text:000085D8 ; switch1:loc_85BC↑j
.text:000085D8 RSB R0, R1, R0 ; jumptable 000085B0 case 1
.text:000085DC POP {R4,PC}
.text:000085E0 ; ---------------------------------------------------------------------------
.text:000085E0
.text:000085E0 loc_85E0 ; CODE XREF: switch1+10↑j
.text:000085E0 ; switch1:loc_85B8↑j
.text:000085E0 ADD R0, R1, R0 ; jumptable 000085B0 case 0
.text:000085E4 POP {R4,PC}
.text:000085E8 ; ---------------------------------------------------------------------------
.text:000085E8
.text:000085E8 def_85B0 ; CODE XREF: switch1+10↑j
.text:000085E8 ; switch1:loc_85B4↑j
.text:000085E8 ADD R0, R1, R0 ; jumptable 000085B0 default case
.text:000085EC POP {R4,PC}
.text:000085EC ; } // starts at 85A0
.text:000085EC ; End of function switch1
.text:000085EC
.text:000085F0
.text:000085F0 ; =============== S U B R O U T I N E =======================================
.text:000085F0
.text:000085F0 ; arg0
.text:000085F0 ;
.text:000085F0
.text:000085F0 ; int __cdecl main(int argc, const char **argv, const char **envp)
.text:000085F0 main ; CODE XREF: j_main↑j
.text:000085F0 ; __unwind {
.text:000085F0 MOV R0, #3
.text:000085F4 PUSH {R4,LR}
.text:000085F8 MOV R2, R0 ; arg2
.text:000085FC MOV R1, #5 ; arg1
.text:00008600 BL switch1 ; arg2 = arg2 - 1
.text:00008604 MOV R1, R0
.text:00008608 LDR R0, =(aSwitch1D - 0x8614) ; "switch1:%d\n"
.text:0000860C ADD R0, PC, R0 ; "switch1:%d\n"
.text:00008610 BL printf
.text:00008614 MOV R0, #0
.text:00008618 POP {R4,PC}
.text:00008618 ; End of function main
.text:00008618
.text:00008618 ; ---------------------------------------------------------------------------