From: ol.sc <ol.sc@b7a2c559-68d2-44c3-8de9-860c34a00d81>
Date: Mon, 2 May 2011 11:23:30 +0000 (+0000)
Subject: Computed pixel aspect ratio (PAR) by presuming a display aspect ratio (DAR) of 4... 
X-Git-Tag: V2.13.3~443
X-Git-Url: https://git.sur5r.net/?a=commitdiff_plain;h=d72d373e8353d086987f516f42a90d79d6d637a6;p=cc65

Computed pixel aspect ratio (PAR) by presuming a display aspect ratio (DAR) of 4/3 for a classic CRT and using the given driver resolutions as storage aspect ratio (SAR).

git-svn-id: svn://svn.cc65.org/cc65/trunk@5017 b7a2c559-68d2-44c3-8de9-860c34a00d81
---

diff --git a/libsrc/geos/devel/geos-tgi.s b/libsrc/geos/devel/geos-tgi.s
index d7484b47f..247920df1 100644
--- a/libsrc/geos/devel/geos-tgi.s
+++ b/libsrc/geos/devel/geos-tgi.s
@@ -48,7 +48,7 @@ yres:   .word   200                     ; Y resolution
 pages:	.byte   1                       ; Number of screens available
         .byte   8                       ; System font X size
         .byte   8                       ; System font Y size
-        .word   $100                    ; Aspect ratio: 1.0
+aspect: .word   $00D4                   ; Aspect ratio (based on 4/3 display)
 
 ; Next comes the jump table. With the exception of IRQ, all entries must be
 ; valid, and may point to an RTS for test versions (function not implemented).
@@ -139,10 +139,13 @@ INSTALL:
 	; check for VDC version and update register $19 value
 
 @L80:
-	lda	#<640
-	ldx	#>640
-	sta	xres
-	stx	xres+1
+	; double the x resolution and halve the aspect ratio
+
+	asl	xres
+	rol	xres+1
+
+	lsr	aspect+1
+	ror	aspect
 
 	; update number of available screens