From d72d373e8353d086987f516f42a90d79d6d637a6 Mon Sep 17 00:00:00 2001
From: "ol.sc"
Date: Mon, 2 May 2011 11:23:30 +0000
Subject: [PATCH] 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
---
libsrc/geos/devel/geos-tgi.s | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
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
--
2.39.5