Overview
| Comment: | don't clobber callee-saved registers |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
481509e13402141fbdaf5072c2e75a03 |
| User & Date: | lexi on 2019-10-21 04:28:46 |
| Other Links: | manifest | tags |
Context
|
2019-10-22
| ||
| 22:21 | Add errno locations for Android, as an initial step check-in: 357c708c52 user: glow tags: trunk | |
| 19:43 | Add default errno locations for building on Android with Termux Should probably be revised, but this is a starting point. Leaf check-in: 960d952eed user: glowpelt tags: BAD | |
|
2019-10-21
| ||
| 04:28 | don't clobber callee-saved registers check-in: 481509e134 user: lexi tags: trunk | |
| 01:46 | fix broken commit check-in: bdb84af41a user: lexi tags: trunk | |
Changes
Modified mod/kcore/syscall.fn.x86.lin.64.s from [856b7532d5] to [3fa83c18de].
31
32
33
34
35
36
37
38
39
40
41
42
43
44
..
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
|
; locals: rbx = s64* result ; r12 = u64* errno ; arg 0 = s64* result ; arg 1 = errno ptr ; arg 2 = syscall num ; arg 3 = valency ; arg 4 = args ptr ; store the locals in registers that ; are guaranteed not to be clobbered, ; saving us some cycles pushing to ; and popping back from the stack mov rbx, ccall.reg.0 mov r12, ccall.reg.1 ................................................................................ js .error ; jump if sign flag set ; move our return values into place and ; return to the caller (which should ; always be k_platform_syscall, btw) mov [rbx], sys.reg.ret mov qword [r12], 0 ; no error ret ; an error was returned - we need to set ; the errno to its positive equivalent, ; and store -1 in the return variable .error: neg sys.reg.ret mov qword [rbx], -1 mov [r12], sys.reg.ret ret |
>
>
>
>
>
>
>
|
>
>
>
>
|
|
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
..
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
|
; locals: rbx = s64* result ; r12 = u64* errno ; arg 0 = s64* result ; arg 1 = errno ptr ; arg 2 = syscall num ; arg 3 = valency ; arg 4 = args ptr ; we use two registers that are supposed ; to be callee-saved, so we need to ; push them to the stack and then pop ; them back off just before the fn rets. push rbx push r12 ; store the locals in registers that ; are guaranteed not to be clobbered, ; saving us some cycles pushing to ; and popping back from the stack mov rbx, ccall.reg.0 mov r12, ccall.reg.1 ................................................................................ js .error ; jump if sign flag set ; move our return values into place and ; return to the caller (which should ; always be k_platform_syscall, btw) mov [rbx], sys.reg.ret mov qword [r12], 0 ; no error jmp .return ; an error was returned - we need to set ; the errno to its positive equivalent, ; and store -1 in the return variable .error: neg sys.reg.ret mov qword [rbx], -1 mov [r12], sys.reg.ret jmp .return .return: pop r12 pop rbx ret |