Append:
49b4e8: c0 ae 47 00 00 00 00 shrb $0, 71(%rsi)
在2023年9月26日星期二 UTC+8 22:43:27<j2gg0s> 写道：
> How to understand assmbly code ` 47ae26: 48 8d 0d bb 06 02 00
> leaq 132795(%rip), %rcx # 0x49b4e8 <go:func.*+0x220>`
>
> Go code:
> ```
> //go:noinline
> func add(a, b int) int {
> defer func() {
> fmt.Println(3)
> }()
> return a + b
> }
>
> func main() {
> add(10, 20)
> }
> ```
>
> Build by `GOOS=linux GOARCH=amd64 GOSSAFUNC=main.add go21 build main.go`
>
> Assembly code
> ```
> objdump -D -S main | grep "main.add>:" -A 30
> 000000000047ae00 <main.add>:
> ; func add(a, b int) int {
> 47ae00: 49 3b 66 10 cmpq 16(%r14), %rsp
> 47ae04: 76 5b jbe 0x47ae61 <main.add+0x61>
> 47ae06: 55 pushq %rbp
> 47ae07: 48 89 e5 movq %rsp, %rbp
> 47ae0a: 48 83 ec 18 subq $24, %rsp
> 47ae0e: 66 44 0f d6 7c 24 10 movq %xmm15, 16(%rsp)
> 47ae15: c6 44 24 07 00 movb $0, 7(%rsp)
> 47ae1a: 48 c7 44 24 08 00 00 00 00 movq $0, 8(%rsp)
> ; return a + b
> 47ae23: 48 01 d8 addq %rbx, %rax
> ; defer func() {
> 47ae26: 48 8d 0d bb 06 02 00 leaq 132795(%rip), %rcx #
> 0x49b4e8 <go:func.*+0x220>
> 47ae2d: 48 89 4c 24 10 movq %rcx, 16(%rsp)
> 47ae32: c6 44 24 07 01 movb $1, 7(%rsp)
> ; return a + b
> 47ae37: 48 89 44 24 08 movq %rax, 8(%rsp)
> 47ae3c: c6 44 24 07 00 movb $0, 7(%rsp)
> 47ae41: e8 7a 00 00 00 callq 0x47aec0 <main.add.func1>
> 47ae46: 48 8b 44 24 08 movq 8(%rsp), %rax
> 47ae4b: 48 83 c4 18 addq $24, %rsp
> 47ae4f: 5d popq %rbp
> 47ae50: c3 retq
> 47ae51: e8 8a 47 fb ff callq 0x42f5e0
> <runtime.deferreturn>
> 47ae56: 48 8b 44 24 08 movq 8(%rsp), %rax
> 47ae5b: 48 83 c4 18 addq $24, %rsp
> 47ae5f: 5d popq %rbp
> 47ae60: c3 retq
> ; func add(a, b int) int {
> 47ae61: 48 89 44 24 08 movq %rax, 8(%rsp)
> ```
>
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