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#include <setjmp.h>
#define JB_SP 0
#define JB_FP 1
#define JB_PC 2
#define ENV(base,reg) [%base + (reg * 4)]
#define ST_FLUSH_WINDOWS 3
#define RW_FP [%fp + 0x48]
.text
.global __longjmp
__longjmp:
/* Store our arguments in global registers so we can still
use them while unwinding frames and their register windows. */
ld ENV(o0,JB_FP), %g3 /* Cache target FP in register %g3. */
mov %o0, %g1 /* ENV in %g1 */
orcc %o1, %g0, %g2 /* VAL in %g2 */
be,a 0f /* Branch if zero; else skip delay slot. */
mov 1, %g2 /* Delay slot only hit if zero: VAL = 1. */
0:
xor %fp, %g3, %o0
add %fp, 512, %o1
andncc %o0, 4095, %o0
bne .Lthread
cmp %o1, %g3
bl .Lthread
/* Now we will loop, unwinding the register windows up the stack
until the restored %fp value matches the target value in %g3. */
.Lloop:
cmp %fp, %g3 /* Have we reached the target frame? */
bl,a .Lloop /* Loop while current fp is below target. */
restore /* Unwind register window in delay slot. */
be,a .Lfound /* Better have hit it exactly. */
ld ENV(g1,JB_SP), %o0 /* Delay slot: extract target SP. */
.Lthread:
/*
* Do a "flush register windows trap". The trap handler in the
* kernel writes all the register windows to their stack slots, and
* marks them all as invalid (needing to be sucked up from the
* stack when used). This ensures that all information needed to
* unwind to these callers is in memory, not in the register
* windows.
*/
ta ST_FLUSH_WINDOWS
ld ENV(g1,JB_PC), %o7 /* Set return PC. */
ld ENV(g1,JB_SP), %fp /* Set saved SP on restore below. */
sub %fp, 64, %sp /* Allocate a register frame. */
st %g3, RW_FP /* Set saved FP on restore below. */
retl
restore %g2, 0, %o0 /* Restore values from above register frame. */
.Lfound:
/* We have unwound register windows so %fp matches the target. */
mov %o0, %sp /* OK, install new SP. */
.Lsp_ok:
ld ENV(g1,JB_PC), %o0 /* Extract target return PC. */
jmp %o0 + 8 /* Return there. */
mov %g2, %o0 /* Delay slot: set return value. */
.size __longjmp, . - __longjmp
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