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[16.git] / 16 / xw / mxpn.asm

diff --git a/16/xw/mxpn.asm b/16/xw/mxpn.asm
new file mode 100755 (executable)
index 0000000..eaaf61b
--- /dev/null
+++ b/16/xw/mxpn.asm
@@ -0,0 +1,60 @@
+;-----------------------------------------------------------\r
+;\r
+; MXPN.ASM - Panning function\r
+; Copyright (c) 1993,1994 by Alessandro Scotti\r
+;\r
+;-----------------------------------------------------------\r
+WARN    PRO\r
+INCLUDE MODEX.DEF\r
+\r
+PUBLIC  mxPan\r
+\r
+EXTRN   mxWaitDisplay   : FAR\r
+EXTRN   mxStartAddress  : FAR\r
+\r
+MX_TEXT         SEGMENT USE16 PARA PUBLIC 'CODE'\r
+                ASSUME cs:MX_TEXT, ds:NOTHING, es:NOTHING\r
+\r
+EXTRN   mx_BytesPerLine : WORD\r
+\r
+;-----------------------------------------------------------\r
+;\r
+; Moves the screen.\r
+;\r
+; Input:\r
+;       X, Y    = new X, Y coordinates of view screen\r
+; Output:\r
+;       none\r
+;\r
+mxPan           PROC    FAR\r
+        ARG     Y:WORD,                 \\r
+                X:WORD                  = ARG_SIZE\r
+        ASSUME  ds:NOTHING\r
+        .enter  0\r
+\r
+        mov     ax, [Y]\r
+        mul     [mx_BytesPerLine]\r
+        mov     dx, [X]\r
+        shr     dx, 1\r
+        shr     dx, 1\r
+        add     ax, dx\r
+        push    ax                      ; Push the start address\r
+        call    mxWaitDisplay\r
+        call    mxStartAddress\r
+\r
+        mov     dx, 03DAh               ; Set the pixel pan register\r
+        in      al, dx\r
+        mov     dx, 03C0h\r
+        mov     al, 33h\r
+        out     dx, al\r
+        mov     al, BYTE PTR [X]\r
+        and     al, 3\r
+        shl     al, 1\r
+        out     dx, al\r
+\r
+        xor     ax, ax\r
+        .leave  ARG_SIZE\r
+mxPan           ENDP\r
+\r
+MX_TEXT         ENDS\r
+END\r