code review 133980043: runtime: fix windows signal handlers

src/pkg/runtime/sys_windows_386.s

 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 #include "zasm_GOOS_GOARCH.h"
 #include "../../cmd/ld/textflag.h"
 
 // void runtime·asmstdcall(void *c);
 TEXT runtime·asmstdcall(SB),NOSPLIT,$0
         MOVL    fn+0(FP), BX
@@ skipping 58 matching lines @@
         MOVL    err+0(FP), AX
         MOVL    AX, 0x34(FS)
         RET
 
 // Called by Windows as a Vectored Exception Handler (VEH).
 // First argument is pointer to struct containing
 // exception record and context pointers.
 // Return 0 for 'not handled', -1 for handled.
 TEXT runtime·sigtramp(SB),NOSPLIT,$0-0
         MOVL    ptrs+0(FP), CX
-        SUBL    $28, SP
+        SUBL    $32, SP
 
         // save callee-saved registers
-        MOVL    BX, 12(SP)
+        MOVL    BX, 28(SP)
         MOVL    BP, 16(SP)
         MOVL    SI, 20(SP)
         MOVL    DI, 24(SP)
 
         MOVL    0(CX), BX // ExceptionRecord*
         MOVL    4(CX), CX // Context*
 
         // fetch g
         get_tls(DX)
         CMPL    DX, $0
         JNE     3(PC)
         MOVL    $0, AX // continue
         JMP     done
         MOVL    g(DX), DX
         CMPL    DX, $0
         JNE     2(PC)
         CALL    runtime·badsignal2(SB)
         // call sighandler(ExceptionRecord*, Context*, G*)
         MOVL    BX, 0(SP)
         MOVL    CX, 4(SP)
         MOVL    DX, 8(SP)
         CALL    runtime·sighandler(SB)
         // AX is set to report result back to Windows
+        MOVL    12(SP), AX
 
 done:
         // restore callee-saved registers
         MOVL    24(SP), DI
         MOVL    20(SP), SI
         MOVL    16(SP), BP
-        MOVL    12(SP), BX
-
-        ADDL    $28, SP
+        MOVL    28(SP), BX
+
+        ADDL    $32, SP
         // RET 4 (return and pop 4 bytes parameters)
         BYTE $0xC2; WORD $4
         RET // unreached; make assembler happy
 
 TEXT runtime·ctrlhandler(SB),NOSPLIT,$0
         PUSHL   $runtime·ctrlhandler1(SB)
         CALL    runtime·externalthreadhandler(SB)
         MOVL    4(SP), CX
         ADDL    $12, SP
         JMP     CX
@@ skipping 232 matching lines @@
         MOVL    BX, lo-8(SP)
         LEAL    lo-8(SP), BX
         MOVL    BX, ptime-12(SP)
         MOVL    $0, alertable-16(SP)
         MOVL    $-1, handle-20(SP)
         MOVL    SP, BP
         MOVL    runtime·NtWaitForSingleObject(SB), AX
         CALL    AX
         MOVL    BP, SP
         RET