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 31 ; locals: rbx = s64* result 32 32 ; r12 = u64* errno 33 33 ; arg 0 = s64* result 34 34 ; arg 1 = errno ptr 35 35 ; arg 2 = syscall num 36 36 ; arg 3 = valency 37 37 ; arg 4 = args ptr 38 + 39 + ; we use two registers that are supposed 40 + ; to be callee-saved, so we need to 41 + ; push them to the stack and then pop 42 + ; them back off just before the fn rets. 43 + push rbx 44 + push r12 38 45 39 46 ; store the locals in registers that 40 47 ; are guaranteed not to be clobbered, 41 48 ; saving us some cycles pushing to 42 49 ; and popping back from the stack 43 50 mov rbx, ccall.reg.0 44 51 mov r12, ccall.reg.1 ................................................................................ 82 89 js .error ; jump if sign flag set 83 90 84 91 ; move our return values into place and 85 92 ; return to the caller (which should 86 93 ; always be k_platform_syscall, btw) 87 94 mov [rbx], sys.reg.ret 88 95 mov qword [r12], 0 ; no error 89 - ret 96 + jmp .return 90 97 91 98 ; an error was returned - we need to set 92 99 ; the errno to its positive equivalent, 93 100 ; and store -1 in the return variable 94 101 .error: neg sys.reg.ret 95 102 mov qword [rbx], -1 96 103 mov [r12], sys.reg.ret 97 - ret 104 + jmp .return 105 + 106 + .return: pop r12 107 + pop rbx 108 + ret