From 2d04cacc5322951f187bb17e017c12920ac8ebe2 Mon Sep 17 00:00:00 2001
From: Mark Zbikowski
Date: Thu, 25 Apr 2024 21:24:10 +0100
Subject: MZ is back!

---
 v4.0/src/MAPPER/SIGHAND.ASM | 204 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 204 insertions(+)
 create mode 100644 v4.0/src/MAPPER/SIGHAND.ASM

(limited to 'v4.0/src/MAPPER/SIGHAND.ASM')

diff --git a/v4.0/src/MAPPER/SIGHAND.ASM b/v4.0/src/MAPPER/SIGHAND.ASM
new file mode 100644
index 0000000..2258d1c
--- /dev/null
+++ b/v4.0/src/MAPPER/SIGHAND.ASM
@@ -0,0 +1,204 @@
+page 80,132
+
+title CP/DOS DosSetSigHandler  mapper
+
+        include msc.inc
+
+dosxxx  segment byte public 'dos'
+        assume  cs:dosxxx,ds:nothing,es:nothing,ss:nothing
+
+;**********************************************************************
+;*
+;*   MODULE:   dossetsighandler
+;*
+;*   FILE NAME: dos007.asm
+;*
+;*   CALLING SEQUENCE:
+;*
+;*       push      word    file handle
+;*       push      dword   distance
+;*       push      word    move type
+;*       push@     dword   new pointer
+;*       call      doschgfileptr
+;*
+;*   MODULES CALLED:  PC-DOS Int 21h, ah=42h
+;*
+;*********************************************************************
+
+            public   dossetsighandler
+            .sall
+            .xlist
+            include  macros.inc
+            .list
+
+str         struc
+old_bp      dw       ?
+return      dd       ?
+Signumber   dw       ?          ; signal number
+Action      dw       ?          ; action code
+Prevaction  dd       ?          ; previous action code
+Prevadrs    dd       ?          ; previous vector address
+Routineadrs dd       ?          ; interrupt handler address
+str         ends
+
+; While we hate to do this, we have to.  The following data areas are
+; expected to be in the CODE segment.
+
+NextControlBreakHandler         label   dword
+NextControlBreakHandlerOffset   dw      DummyControlBreakHandler
+NextControlBreakHandlerSegment  dw      dosxxx
+
+NextCriticalErrorHandler        label   dword
+NextCriticalErrorHandlerOffset  dw      DummyCriticalErrorHandler
+NextCriticalErrorHandlerSegment dw      dosxxx
+
+dossetsighandler  proc  far
+
+        Enter    dossetsighandler       ; push registers
+
+        mov      ax,[bp].action         ; get action code
+        cmp      ax,2                   ; action code 2 ??
+        je       continue1              ; branch if true
+        mov      ax,1                   ; else, set error code
+        jmp      exit                   ; return
+
+continue1:
+        mov      ax,[bp].signumber      ; get signel number
+        cmp      ax,1                   ; signal 1 (cntrl chara) ??
+        je       cntrlc                 ; jump if true
+        cmp      ax,4                   ; signal 4 (cntrl chara) ??
+        je       cntrlc                 ; jump if true
+        mov      ax,2                   ; else, set error code
+        jmp      exit                   ; return
+
+cntrlc: mov      ax,03523h
+        int      21h                    ; get old vector address
+
+        lds      si,[bp].prevadrs       ; previous handler pointer
+        mov      word ptr [si],bx       ; save it in prevsdrs
+        mov      word ptr [si]+2,es
+
+        lds      dx,[bp].routineadrs    ; get address of signal  handler
+
+        mov     NextControlBreakHandlerOffset,dx   ; save it
+        mov     NextControlBreakHandlerSegment,ds
+
+        mov     dx,cs
+        mov     ds,dx
+        mov     dx,offset RealControlBreakHandler
+
+        mov      ax,02523H
+        int      21h                   ; set signal handler addrs in vector
+
+        sub      ax,ax                 ; set good return code
+
+exit:   mexit                          ; pop registers
+        ret      size str - 6          ; return
+
+dossetsighandler  endp
+
+        page
+
+;------------------------------------------------------------------------------
+
+; This routine will get control on  control break, and it will make
+;  sure that the environment is acceptable prior to calling the new
+;  handler.  NOTE: we expect the new handler to be written in MicroSoft 'C'
+
+RealControlBreakHandler         proc    far
+
+        push    ds
+        push    es
+        push    di
+        push    si
+        push    bp
+        push    dx
+        push    cx
+        push    bx
+        push    ax
+
+; reestablish the es and ds segment registers before going to 'C'
+
+        mov     ax,seg DGroup
+        mov     ds,ax
+        mov     es,ax
+
+        call    NextControlBreakHandler
+
+        pop     ax
+        pop     bx
+        pop     cx
+        pop     dx
+        pop     bp
+        pop     si
+        pop     di
+        pop     es
+        pop     ds
+
+        iret
+
+RealControlBreakHandler         endp
+
+        page
+
+;------------------------------------------------------------------------------
+
+; This routine will get control on the control break, and it will make
+;  sure that the environment is acceptable prior to calling the new
+;  handler.  NOTE: we expect the new handler to be written in MicroSoft 'C'
+
+RealCriticalErrorHandler        proc    far
+
+        push    ds
+        push    es
+        push    di
+        push    si
+        push    bp
+        push    dx
+        push    cx
+        push    bx
+        push    ax
+
+; reestablish the es and ds segment registers before going to 'C'
+
+        mov     ax,seg DGroup
+        mov     ds,ax
+        mov     es,ax
+
+        call    NextControlBreakHandler
+
+        pop     ax
+        pop     bx
+        pop     cx
+        pop     dx
+        pop     bp
+        pop     si
+        pop     di
+        pop     es
+        pop     ds
+
+        iret
+
+RealCriticalErrorHandler        endp
+
+        page
+
+;------------------------------------------------------------------------------
+
+DummyControlBreakHandler        proc    far
+
+                iret
+
+DummyControlBreakHandler        endp
+
+DummyCriticalErrorHandler       proc    far
+
+                iret
+
+DummyCriticalErrorHandler       endp
+
+
+
+dosxxx      ends
+
+            end
-- 
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