From b4d44860c237c05447f5641f83f19cece2ac9975 Mon Sep 17 00:00:00 2001
From: "B. Watson" <urchlay@slackware.uk>
Date: Tue, 10 Mar 2026 03:30:13 -0400
Subject: really fix the brokenness with MyDOS (close E: device at startup).

---
 memsetup.asm | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

(limited to 'memsetup.asm')

diff --git a/memsetup.asm b/memsetup.asm
index de9c7d9..8e6b4df 100644
--- a/memsetup.asm
+++ b/memsetup.asm
@@ -2,27 +2,28 @@
 ; RAMTOP to $6A00, disables BASIC (on XL/XE), disables ANTIC DMA, then
 ; returns so the rest of the .xex continues to load.
 
-; This is pretty weird: when loading fnchat.xex from MyDOS 4.50 or
-; (apparently) Spartados X, a 0 byte gets written to our display
-; list. It's up in the $BFxx area, which is to say, where the GR.0
-; screen used by DOS lives... and somehow these DOSes are writing a
-; 0 byte to the screen (a space) in the middle of loading the file.
-; Setting SAVMSC to something else ($0600, here) avoids this.
-
  *= $2000
 memsetup
+ ; close the E: device
+ lda #$0c   ; CIO CLOSE command
+ sta $0342  ; ICCOM
+ ldx #0     ; channel 0
+ jsr $E456  ; CIOV
+
+ ; disable BASIC (XL/XE only)
  lda $d301  ; PORTB
- ora #$02   ; disable BASIC (XL/XE only)
+ ora #$02
  sta $d301
  lda #$80
+
+ ; set up everything else
  sta $6a    ; RAMTOP
  sta $02e6  ; MEMTOP high
  lda #0
  sta $02e5  ; MEMTOP low
  sta $022f  ; SDMCTL (turn off screen)
- sta $58    ; SAVMSC
- lda #$06
- sta $59    ; SAVMSC+1
+
+ ; give the SDMCTL change time to get applied by the OS
  lda $14    ; RTCLOK+2
 loop
  cmp $14    ; wait until next frame
-- 
cgit v1.2.3