+;-----------------------------------------------------------\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