setjmp: optimize x86 longjmp epilogues

[musl] / src / setjmp / powerpc64 / longjmp.s

diff --git a/src/setjmp/powerpc64/longjmp.s b/src/setjmp/powerpc64/longjmp.s
index 7f241c2..81d45ff 100644 (file)
--- a/src/setjmp/powerpc64/longjmp.s
+++ b/src/setjmp/powerpc64/longjmp.s
@@ -10,10 +10,14 @@ longjmp:
        # 1) restore cr
        ld   0,  1*8(3)
        mtcr 0
-       # 2) restore r1-r2 (SP and TOC)
+       # 2) restore SP
        ld   1,  2*8(3)
+       # 3) restore TOC into both r2 and the caller's stack.
+       #    Which location is required depends on whether setjmp was called
+       #    locally or non-locally, but it's always safe to restore to both.
        ld   2,  3*8(3)
-       # 3) restore r14-r31
+       std  2,   24(1)
+       # 4) restore r14-r31
        ld  14,  4*8(3)
        ld  15,  5*8(3)
        ld  16,  6*8(3)
@@ -32,7 +36,7 @@ longjmp:
        ld  29, 19*8(3)
        ld  30, 20*8(3)
        ld  31, 21*8(3)
-       # 4) restore floating point registers f14-f31
+       # 5) restore floating point registers f14-f31
        lfd 14, 22*8(3)
        lfd 15, 23*8(3)
        lfd 16, 24*8(3)
@@ -52,7 +56,7 @@ longjmp:
        lfd 30, 38*8(3)
        lfd 31, 39*8(3)
 
-       # 5) restore vector registers v20-v31
+       # 6) restore vector registers v20-v31
        addi 3, 3, 40*8
        lvx 20, 0, 3 ; addi 3, 3, 16
        lvx 21, 0, 3 ; addi 3, 3, 16
@@ -67,7 +71,7 @@ longjmp:
        lvx 30, 0, 3 ; addi 3, 3, 16
        lvx 31, 0, 3
 
-       # 6) return r4 ? r4 : 1
+       # 7) return r4 ? r4 : 1
        mr    3,   4
        cmpwi cr7, 4, 0
        bne   cr7, 1f