From: Alan Cox <alan@etchedpixels.co.uk>
Date: Mon, 10 Nov 2014 21:53:08 +0000 (+0000)
Subject: bootrom: Some corrections from Manuel Pazos
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=711675f473723fd8c21e908dfcb33416e82082e4;p=FUZIX.git

bootrom: Some corrections from Manuel Pazos

Plus some tidying of them to match the sdcc assembler

Still doesn't work but its hopefully closer now
---

diff --git a/Kernel/platform-msx1/bootrom.s b/Kernel/platform-msx1/bootrom.s
index f7db4fc1..951b0c68 100644
--- a/Kernel/platform-msx1/bootrom.s
+++ b/Kernel/platform-msx1/bootrom.s
@@ -15,20 +15,55 @@ wtfami:		di
 		ld a, #':'
 		out (0x2f), a
 
+; Select RAM subslot in all pages
+		ld a,(0xffff)		; Subslot register
+		cpl
+		and #0xc0		; RAM subslot (RAM in page 3)
+		ld e, a
+		rrca			; Propogate into other pages
+		rrca
+		or e
+		rrca
+		rrca
+		or e
+		rrca
+		rrca
+		or e
+		ld (0xffff),a		; All pages with the same subslot
 		in a, (0xA8)
 		ld d, a
 		and #0x0C		; bits for 0x4000
 		ld b, a
-		rla
-		rla			; to 0x8000
+		rlca
+		rlca			; to 0x8000
 		or b			; and 0x4000
-		rla
-		rla			; to 0xC000/8000
+		rlca
+		rlca			; to 0xC000/8000
 		or b			; and 0x4000
 		ld b, a			; B is now the bits for
 					; putting 48K of cartridge
 					; in place
+; Select RAM in page 0
+		ld a,d			; Page 3 must be RAM
+		and #0xc0
+		rlca
+		rlca
+		or b			; Pages 3-1 = Cartridge, Page 0 = RAM
 		out (0xA8), a		; Map cartridge
+
+; Select the subslot of the cartridge in pages 3, 2, 1
+		ld a, (0xffff)
+		cpl
+		and #0x0C		; Cartridge in page 1
+		ld c, a
+		rlca
+		rlca			; to 0x8000
+		or c			; and 0x4000
+		rlca
+		rlca			; to 0xC000/8000
+		or c			; and 0x4000
+		ld (0xffff), a		; Select the subslot of the cartridge
+
 		ld a, #3
 		out (0xFC), a		; Begin mapping RAM
 		ld a, #'1'
@@ -90,5 +125,6 @@ ramgo:		ld a, #'!'
 		out (0xA8), a		; Now go all ram
 		jp 0x100
 
-		; Hack Hack FIXME
-		.ds 0x72
+		; Put start at 0x100 so we can boot the MSXDOS .com too
+		; Hack
+		.ds 0x49