1 files changed, 81 insertions, 0 deletions

diff --git a/v4.0/src/MAPPER/REALLSEG.ASM b/v4.0/src/MAPPER/REALLSEG.ASM
new file mode 100644
index 0000000..352a091
--- /dev/null
+++ b/v4.0/src/MAPPER/REALLSEG.ASM
@@ -0,0 +1,81 @@
+;
+page 60,132
+;
+title CP/DOS  DosReallocSeg  mapper
+;
+dosxxx  segment byte public 'dos'
+        assume  cs:dosxxx,ds:nothing,es:nothing,ss:nothing
+;
+; ************************************************************************* *
+; *
+; *      MODULE: DosReallocSeg
+; *
+; *      FILE NAME: dos043.asm
+; *
+; *      FUNCTION: This module changes the size of a segment already
+; *             allocated
+; *
+; *      CALLING SEQUENCE:
+; *
+; *             push    size            ; new segment size requested in bytes
+; *             push    selector        ; selector
+; *             call    dosreallocseg
+; *
+; *      RETURN SEQUENCE:
+; *
+; *
+; *
+; *      MODULES CALLED:  DOS Int 21, AH=4A
+; *
+; *
+; *
+; *************************************************************************
+;
+        public  dosreallocseg
+        .sall
+        .xlist
+        include macros.inc
+        .list
+
+str     struc
+old_bp  dw      ?
+return  dd      ?
+Selector        dw      ?       ; segment selector
+SegmentSize     dw      ?       ; new segment size in bytes
+str     ends
+
+dosreallocseg proc   far
+        Enter   dosreallocseg           ; save registers
+
+        mov     bx,[bp].SegmentSize     ; Get new segment size
+        cmp     bx,0                    ; check for 0
+        je      AllocateMax             ; jmp to full seg
+
+        shr     bx,1                    ; else convert segment in bytes
+        shr     bx,1                    ; paragraph
+        shr     bx,1
+        shr     bx,1
+        jmp     HaveSize
+
+AllocateMax:
+        mov     bx,4096                 ; default segment size in paragraph
+
+HaveSize:
+        mov     es,[bp].Selector        ; set up segment for new size
+
+        mov     ah,4ah                  ; set up for DOS realloc call
+        int     21h                     ; realloc segment
+        jc      ErrorExit               ; jump if error
+
+        sub     ax,ax                   ; else set good return code
+
+ErrorExit:
+        Mexit                           ; restore registers
+
+        ret     size str - 6            ; return
+
+dosreallocseg  endp
+
+dosxxx  ends
+
+        end