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/CHDIR.ASM | 74 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 v4.0/src/MAPPER/CHDIR.ASM

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

diff --git a/v4.0/src/MAPPER/CHDIR.ASM b/v4.0/src/MAPPER/CHDIR.ASM
new file mode 100644
index 0000000..5143b26
--- /dev/null
+++ b/v4.0/src/MAPPER/CHDIR.ASM
@@ -0,0 +1,74 @@
+;
+page 80,132
+;
+title CP/DOS  DosChDir  mapper
+;
+dosxxx  segment byte public 'dos'
+        assume  cs:dosxxx,ds:nothing,es:nothing,ss:nothing
+;
+; ************************************************************************* *
+; *
+; *      MODULE: DosChDir
+; *
+; *      FUNCTION: change directory name
+; *
+; *      FUNCTION: This module will change the current directory for the
+; *                requesting process.
+; *
+; *
+; *      CALLING SEQUENCE:
+; *
+; *                PUSH@ ASCIIZ Dirname ; Directory path name
+; *                PUSH  DWORD  0       ; Reserved (must be zero)  took out @
+; *                                     ; 5/28 to match 3/25 spec
+; *                CALL DosChDir
+; *
+; *
+; *      RETURN SEQUENCE:
+; *
+; *                IF ERROR (AX NOT = 0)
+; *
+; *                   AX = Error Code:
+; *
+; *                   o   Invalid directory path
+; *
+; *      MODULES CALLED:
+; *                     DOS int 21h   function 3Bh ; Change current directory
+; *
+; *************************************************************************
+
+        public  DosChDir
+        .sall
+        .xlist
+        include macros.inc
+        .list
+
+str     struc
+old_bp  dw      ?
+return  dd      ?
+dtrm006 dd      0h           ;reserved  (must be zero)
+dnam006 dd      ?            ;address of directory path name
+str     ends
+
+DosChDir  proc   far
+        Enter   DosChDir                 ; push registers
+
+        mov     dx, word ptr [bp].dnam006    ;load directory name offset
+        mov     ax, word ptr [bp].dnam006+2  ;load directory name segment
+
+        push    ax                       ; set segment in DS
+        pop     ds
+
+        mov     ax,03b00h                ; load chdir op code
+        int     21h                      ; call dos to change the directory
+        jc      exit                     ; jump if error
+
+        xor     ax,ax                    ; else, good return code
+exit:   mexit                            ; pop registers
+        ret     size str - 6             ; return
+
+DosChDir  endp
+
+dosxxx  ends
+
+        end
-- 
cgit v1.2.3