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Date: Tue, 11 Aug 2020 21:11:16 +0300
From: Alexander Monakov <amonakov@...ras.ru>
To: musl@...ts.openwall.com
Subject: [PATCH 3/3] setjmp: optimize x86 longjmp epilogues
---
src/setjmp/i386/longjmp.s | 6 ++----
src/setjmp/x32/longjmp.s | 6 ++----
src/setjmp/x86_64/longjmp.s | 6 ++----
3 files changed, 6 insertions(+), 12 deletions(-)
diff --git a/src/setjmp/i386/longjmp.s b/src/setjmp/i386/longjmp.s
index 772d28dd..b429f135 100644
--- a/src/setjmp/i386/longjmp.s
+++ b/src/setjmp/i386/longjmp.s
@@ -14,7 +14,5 @@ longjmp:
mov 4(%edx),%esi
mov 8(%edx),%edi
mov 12(%edx),%ebp
- mov 16(%edx),%ecx
- mov %ecx,%esp
- mov 20(%edx),%ecx
- jmp *%ecx
+ mov 16(%edx),%esp
+ jmp *20(%edx)
diff --git a/src/setjmp/x32/longjmp.s b/src/setjmp/x32/longjmp.s
index e709acad..bb88afa1 100644
--- a/src/setjmp/x32/longjmp.s
+++ b/src/setjmp/x32/longjmp.s
@@ -16,7 +16,5 @@ longjmp:
mov 24(%rdi),%r13
mov 32(%rdi),%r14
mov 40(%rdi),%r15
- mov 48(%rdi),%rdx /* this ends up being the stack pointer */
- mov %rdx,%rsp
- mov 56(%rdi),%rdx /* this is the instruction pointer */
- jmp *%rdx /* goto saved address without altering rsp */
+ mov 48(%rdi),%rsp
+ jmp *56(%rdi) /* goto saved address without altering rsp */
diff --git a/src/setjmp/x86_64/longjmp.s b/src/setjmp/x86_64/longjmp.s
index e709acad..bb88afa1 100644
--- a/src/setjmp/x86_64/longjmp.s
+++ b/src/setjmp/x86_64/longjmp.s
@@ -16,7 +16,5 @@ longjmp:
mov 24(%rdi),%r13
mov 32(%rdi),%r14
mov 40(%rdi),%r15
- mov 48(%rdi),%rdx /* this ends up being the stack pointer */
- mov %rdx,%rsp
- mov 56(%rdi),%rdx /* this is the instruction pointer */
- jmp *%rdx /* goto saved address without altering rsp */
+ mov 48(%rdi),%rsp
+ jmp *56(%rdi) /* goto saved address without altering rsp */
--
2.11.0
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