ARM处理器函数调用时的参数传递

 

对于ARM32架构，函数调用时前4个参数用通用寄存器（R0~3），剩余的用栈。对于ARM64架构，函数调用时前8个参数用通用寄存器(R0~7)，剩余的通过栈。

测试程序：

 1 #include <stdio.h>
 2 
 3 int func(int a, int b, int c, int *e, int f, int *g, int h, int i, int j, int *k)
 4 {
 5 
 6         return a+b+c+*e+f+*g+h+i+j+*k;
 7 }
 8 
 9 int main(int argc, const char *argv[])
10 {
11         int e = 4, g=6, k=10;
12 
13         printf("%d\n", func(1, 2, 3, &e, 5, &g, 7, 8, 9, &k));
14 
15         return 0;
16 }

 

对应的汇编（-S）：

ARM32：

  1     .arch armv7-a
  2     .eabi_attribute 28, 1
  3     .eabi_attribute 20, 1
  4     .eabi_attribute 21, 1
  5     .eabi_attribute 23, 3
  6     .eabi_attribute 24, 1
  7     .eabi_attribute 25, 1
  8     .eabi_attribute 26, 2
  9     .eabi_attribute 30, 6
 10     .eabi_attribute 34, 1
 11     .eabi_attribute 18, 4
 12     .file    "a.c"
 13     .text
 14     .align    1
 15     .global    func
 16     .syntax unified
 17     .thumb
 18     .thumb_func
 19     .fpu vfpv3-d16
 20     .type    func, %function
 21 func:
 22     @ args = 24, pretend = 0, frame = 16
 23     @ frame_needed = 1, uses_anonymous_args = 0
 24     @ link register save eliminated.
 25     push    {r7}
 26     sub    sp, sp, #20
 27     add    r7, sp, #0
 28     str    r0, [r7, #12]
 29     str    r1, [r7, #8]
 30     str    r2, [r7, #4]
 31     str    r3, [r7]
 32     ldr    r2, [r7, #12]
 33     ldr    r3, [r7, #8]
 34     add    r2, r2, r3
 35     ldr    r3, [r7, #4]
 36     add    r2, r2, r3
 37     ldr    r3, [r7]
 38     ldr    r3, [r3]
 39     add    r2, r2, r3
 40     ldr    r3, [r7, #24]
 41     add    r2, r2, r3
 42     ldr    r3, [r7, #28]
 43     ldr    r3, [r3]
 44     add    r2, r2, r3
 45     ldr    r3, [r7, #32]
 46     add    r2, r2, r3
 47     ldr    r3, [r7, #36]
 48     add    r2, r2, r3
 49     ldr    r3, [r7, #40]
 50     add    r2, r2, r3
 51     ldr    r3, [r7, #44]
 52     ldr    r3, [r3]
 53     add    r3, r3, r2
 54     mov    r0, r3
 55     adds    r7, r7, #20
 56     mov    sp, r7
 57     @ sp needed
 58     ldr    r7, [sp], #4
 59     bx    lr
 60     .size    func, .-func
 61     .section    .rodata
 62     .align    2
 63 .LC0:
 64     .ascii    "%d\012\000"
 65     .text
 66     .align    1
 67     .global    main
 68     .syntax unified
 69     .thumb
 70     .thumb_func
 71     .fpu vfpv3-d16
 72     .type    main, %function
 73 main:
 74     @ args = 0, pretend = 0, frame = 24
 75     @ frame_needed = 1, uses_anonymous_args = 0
 76     push    {r7, lr}
 77     sub    sp, sp, #48
 78     add    r7, sp, #24
 79     str    r0, [r7, #4]
 80     str    r1, [r7]
 81     movs    r3, #4
 82     str    r3, [r7, #20]
 83     movs    r3, #6
 84     str    r3, [r7, #16]
 85     movs    r3, #10
 86     str    r3, [r7, #12]
 87     add    r2, r7, #20
 88     add    r3, r7, #12
 89     str    r3, [sp, #20]
 90     movs    r3, #9
 91     str    r3, [sp, #16]
 92     movs    r3, #8
 93     str    r3, [sp, #12]
 94     movs    r3, #7
 95     str    r3, [sp, #8]
 96     add    r3, r7, #16
 97     str    r3, [sp, #4]
 98     movs    r3, #5
 99     str    r3, [sp]
100     mov    r3, r2
101     movs    r2, #3
102     movs    r1, #2
103     movs    r0, #1
104     bl    func
105     mov    r3, r0
106     mov    r1, r3
107     movw    r0, #:lower16:.LC0
108     movt    r0, #:upper16:.LC0
109     bl    printf
110     movs    r3, #0
111     mov    r0, r3
112     adds    r7, r7, #24
113     mov    sp, r7
114     @ sp needed
115     pop    {r7, pc}
116     .size    main, .-main
117     .ident    "GCC: (Linaro GCC 7.3-2018.05) 7.3.1 20180425 [linaro-7.3-2018.05 revision d29120a424ecfbc167ef90065c0eeb7f91977701]"
118     .section    .note.GNU-stack,"",%progbits

 在调用func函数时（bl func），参数存放情况如下：

 

ARM64：

 1     .arch armv8-a
 2     .file    "a.c"
 3     .text
 4     .align    2
 5     .global    func
 6     .type    func, %function
 7 func:
 8     sub    sp, sp, #48
 9     str    w0, [sp, 44]
10     str    w1, [sp, 40]
11     str    w2, [sp, 36]
12     str    x3, [sp, 24]
13     str    w4, [sp, 32]
14     str    x5, [sp, 16]
15     str    w6, [sp, 12]
16     str    w7, [sp, 8]
17     ldr    w1, [sp, 44]
18     ldr    w0, [sp, 40]
19     add    w1, w1, w0
20     ldr    w0, [sp, 36]
21     add    w1, w1, w0
22     ldr    x0, [sp, 24]
23     ldr    w0, [x0]
24     add    w1, w1, w0
25     ldr    w0, [sp, 32]
26     add    w1, w1, w0
27     ldr    x0, [sp, 16]
28     ldr    w0, [x0]
29     add    w1, w1, w0
30     ldr    w0, [sp, 12]
31     add    w1, w1, w0
32     ldr    w0, [sp, 8]
33     add    w1, w1, w0
34     ldr    w0, [sp, 48]
35     add    w1, w1, w0
36     ldr    x0, [sp, 56]
37     ldr    w0, [x0]
38     add    w0, w1, w0
39     add    sp, sp, 48
40     ret
41     .size    func, .-func
42     .section    .rodata
43     .align    3
44 .LC0:
45     .string    "%d\n"
46     .text
47     .align    2
48     .global    main
49     .type    main, %function
50 main:
51     sub    sp, sp, #64
52     stp    x29, x30, [sp, 16]
53     add    x29, sp, 16
54     str    w0, [x29, 28]
55     str    x1, [x29, 16]
56     mov    w0, 4
57     str    w0, [x29, 44]
58     mov    w0, 6
59     str    w0, [x29, 40]
60     mov    w0, 10
61     str    w0, [x29, 36]
62     add    x2, x29, 40
63     add    x1, x29, 44
64     add    x0, x29, 36
65     str    x0, [sp, 8]
66     mov    w0, 9
67     str    w0, [sp]
68     mov    w7, 8
69     mov    w6, 7
70     mov    x5, x2
71     mov    w4, 5
72     mov    x3, x1
73     mov    w2, 3
74     mov    w1, 2
75     mov    w0, 1
76     bl    func
77     mov    w1, w0
78     adrp    x0, .LC0
79     add    x0, x0, :lo12:.LC0
80     bl    printf
81     mov    w0, 0
82     ldp    x29, x30, [sp, 16]
83     add    sp, sp, 64
84     ret
85     .size    main, .-main
86     .ident    "GCC: (Linaro GCC 7.3-2018.05) 7.3.1 20180425 [linaro-7.3-2018.05 revision d29120a424ecfbc167ef90065c0eeb7f91977701]"
87     .section    .note.GNU-stack,"",@progbits

 在调用func时（bl func）时，参数的存放情况如下：

完。

posted @ 2020-08-02 23:05  摩斯电码  阅读(2604)  评论(0)  编辑  收藏  举报