From 79e3ac1a26211f8abf029a553617dad32f44befe Mon Sep 17 00:00:00 2001
From: ceriel <none@none>
Date: Wed, 20 Apr 1988 16:58:29 +0000
Subject: [PATCH] improved setjmp

---
 lang/cem/libcc/gen/setjmp.e | 60 +++++++------------------------------
 1 file changed, 11 insertions(+), 49 deletions(-)

diff --git a/lang/cem/libcc/gen/setjmp.e b/lang/cem/libcc/gen/setjmp.e
index 8bc5af41f..9dedbc2c1 100644
--- a/lang/cem/libcc/gen/setjmp.e
+++ b/lang/cem/libcc/gen/setjmp.e
@@ -7,8 +7,6 @@
 ;  -----------------
 ; |   signal mask   |		(only for Berkeley 4.2)
 ;  -----------------
-; |   PC of caller  |
-;  -----------------
 ; |                 |
 ; |  GTO descriptor |
 ; |   (SP, LB, PC)  |
@@ -16,19 +14,13 @@
 ;  -----------------
 ;
 ; setjmp saves the signalmask, PC, SP, and LB of caller, and creates a
-; GTO descriptor with a program counter indicating a piece of code that
-; gets the return value right before jumping to the caller of setjmp in
-; the setjmp buffer, which has a layout as displayed above.
-; The big problem here is how to het the return address, i.e. the PC of
+; GTO descriptor from this.
+; The big problem here is how to get the return address, i.e. the PC of
 ; the caller; This problem is solved by the front-end, which must pass
 ; it as an extra parameter to setjmp.
 
 gtobuf
  bss 3*EM_PSIZE,0,0
-retval
- bss EM_WSIZE,0,0
-jmpbuf_addr
- bss EM_PSIZE,0,0
 
  inp $fill_ret_area
  exp $setjmp
@@ -41,50 +33,23 @@ jmpbuf_addr
  lfr EM_WSIZE
  lal 0
  loi EM_PSIZE
- stf 4*EM_PSIZE
+ stf 3*EM_PSIZE
 #endif
  ; create GTO descriptor for longjmp
  lxl 0
  dch		; Local Base of caller
  lxa 0		; Stackpointer of caller
-.1
- rom *1
- lae .1
- loi EM_PSIZE	; where the longjmp ends up
- lal 0
- loi EM_PSIZE
- sti 3*EM_PSIZE	; stored in jmpbuf
- ; also save return address, which has been supplied by the compiler
  lal EM_PSIZE
  loi EM_PSIZE
  lal 0
  loi EM_PSIZE
- adp 3*EM_PSIZE
- sti EM_PSIZE
+ sti 3*EM_PSIZE	; stored in jmpbuf
  loc 0
  ret EM_WSIZE
-1
- ; so, the longjmp returns here.
- ; now, create a GTO descriptor for the final GTO
- lae jmpbuf_addr
- loi EM_PSIZE
- adp 3*EM_PSIZE
- loi EM_PSIZE
- lae gtobuf
- sti EM_PSIZE	; this is the return address
- lae jmpbuf_addr
- loi EM_PSIZE
- adp EM_PSIZE
- loi 2*EM_PSIZE
- lae gtobuf+EM_PSIZE
- sti 2*EM_PSIZE	; that's it, the GTO descriptor is ready;
-		; now take care of the return value ...
- cal $fill_ret_area
- gto gtobuf	; there we go ...
  end 0
 
  pro $fill_ret_area,0
- loe retval
+ lol 0
  ret EM_WSIZE
  end 0
 
@@ -94,14 +59,14 @@ jmpbuf_addr
  loi EM_PSIZE
 #ifdef __BSD4_2
  dup EM_PSIZE
- lof 4*EM_PSIZE
+ lof 3*EM_PSIZE
  cal $sigsetmask
  asp EM_WSIZE
  lfr EM_WSIZE
  asp EM_WSIZE
 #endif
- lae jmpbuf_addr
- sti EM_PSIZE	; save address of jmpbuf
+ lae gtobuf
+ blm 3*EM_PSIZE
  lol EM_PSIZE
  dup EM_WSIZE
  zne *3
@@ -109,10 +74,7 @@ jmpbuf_addr
  asp EM_WSIZE
  loc 1
 3
- ste retval	; save return value
- lal 0
- loi EM_PSIZE
- lae gtobuf
- blm 3*EM_PSIZE	; create GTO descriptor
- gto gtobuf	; and GTO
+ cal $fill_ret_area
+ asp EM_WSIZE
+ gto gtobuf	; there we go ...
  end 0
-- 
2.34.1