cosmopolitan/libc/nexgen32e/gclongjmp.S

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/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
vi: set et ft=asm ts=8 sw=8 fenc=utf-8 :vi
Copyright 2020 Justine Alexandra Roberts Tunney
This program is free software; you can redistribute it and/or modify │
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License. │
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of │
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software │
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include "libc/macros.h"
/ Jumps up stack to previous setjmp() invocation.
/
/ This is the same as longjmp() but also unwinds the stack to free
/ memory, etc. that was registered using gc() or defer(). If GC
/ isn't linked, this behaves the same as longjmp().
/
/ @param rdi points to the jmp_buf which must be the same stack
/ @param esi is returned by setjmp() invocation (coerced nonzero)
/ @assume system five nexgen32e abi conformant
/ @see examples/ctrlc.c
/ @noreturn
gclongjmp:
.leafprologue
.profilable
.weak g_garbage
lea g_garbage(%rip),%r12
test %r12,%r12
jnz .L.unwind.destructors
0: jmp longjmp
.L.unwind.destructors:
push %rdi
push %rsi
mov (%r12),%r13 # garbage.i
mov 16(%r12),%r14 # garbage.p
mov (%rdi),%r15 # jmp_buf[0] is new %rsp
shl $5,%r13
1: test %r13,%r13
jz 2f
sub $32,%r13
cmp (%r14,%r13),%r15
ja 2f
mov 8(%r14,%r13),%rax # garbage.p[𝑖].fn
mov 16(%r14,%r13),%rdi # garbage.p[𝑖].arg
call *%rax
decq (%r12)
jmp 1b
2: pop %rsi
pop %rdi
jmp 0b
.endfn gclongjmp,globl
.source __FILE__