From d98e0b902ed803452c1ebe43aa963c69660a8e94 Mon Sep 17 00:00:00 2001
From: Steveneska <steveneska@outlook.com>
Date: Fri, 3 Nov 2023 12:33:47 +0800
Subject: [PATCH] Update MegaFlashROM SCC+ SD Boot Behavior

This PR gives the MegaFlashROM the same boot behavior as the Sunrise IDE driver 0.1.7, that is restore the MSX saved screen parameters at boot if they've been saved by the RTC on MSX2 or higher computers.

Given that I'm currently traveling, I was only able to test and confirm it working with OpenMSX on a FS-A1WSX and FS-A1GT using both 1 and 2 slots flavors of the ROM.

Thankfully the changes made shouldn't bring up any unrelated behaviors since they're cosmetic at most and don't affect the driver itself.
---
 .../kernel/drivers/MegaFlashRomSD/mfrsd.asm   | 84 ++++++++++++++++---
 1 file changed, 72 insertions(+), 12 deletions(-)

diff --git a/source/kernel/drivers/MegaFlashRomSD/mfrsd.asm b/source/kernel/drivers/MegaFlashRomSD/mfrsd.asm
index 63825574..0c15c63a 100644
--- a/source/kernel/drivers/MegaFlashRomSD/mfrsd.asm
+++ b/source/kernel/drivers/MegaFlashRomSD/mfrsd.asm
@@ -68,10 +68,21 @@ CODE_ADD:	equ	0F2EDh
 
 ; BIOS
 ENASLT:		equ	#24
+INITXT		equ	#6C
 CHGET		equ	#9f
 CHPUT		equ	#A2	;Character output
 RSLREG:		equ	#138
-EXPTBL:		equ	#FCC1		
+EXTROM		equ	#15F
+
+SDFSCR		equ	#185
+REDCLK		equ	#1F5
+
+MSXVER		equ	#2D
+LINL40		equ	#F3AE
+LINLEN		equ	#F3B0
+BDRCLR		equ	#F3EB
+SCRMOD		equ	#FCAF
+EXPTBL:		equ	#FCC1
 SLTWRK:		equ	#FD09
 
 ; SD
@@ -357,12 +368,16 @@ DRV_TIMI:
 ;-----------------------------------------------------------------------------
 DRV_INIT:
 		or	a
-		jr	nz,.secondExe	; Second execution
+		jr	nz,.scrnSet
 	
 		ld	hl,WORK_AREA_SIZE
 		;ld	a,NUM_DRIVES
 		ret		;Note that Cy is 0 (no interrupt hooking needed)
 
+.scrnSet:
+		call	USRSCRSET
+		jr	nz,.secondExe	; Second execution
+
 .secondExe:
 		ld	de,TXT_INFO
 		call	PRINT		; Driver info
@@ -1322,7 +1337,7 @@ InitSD:
 	ret	c			; Timeout (card removed or damaged?)
 	ret	nz			; Command error
 
-	;call	GETWRK			; Ya deber�a tener en IX el workarea
+	;call	GETWRK			; Ya debería tener en IX el workarea
 	
 	res	BIT_SDHC,(ix+STATUS)	; Set SDSC as default
 	
@@ -1461,7 +1476,7 @@ MMC_FOUND:
 
 ;-----------------------------------------------------------------------------
 ; Inicializa la SD y pone el modo SPI.
-; Si no se hace as� falla en el FS-A1.
+; Si no se hace así falla en el FS-A1.
 ; Aparentemente, si se escribe el CRC (#95) desde un registro falla.
 ;-----------------------------------------------------------------------------
 SD_INIT:
@@ -1603,7 +1618,7 @@ SD_CMD:
 	ld	b,0
 SD_CMD2:
 	ld	a,(de)
-	cp	#ff		; Aqu� se podr�a mirar solo el bit 7? 0=ready
+	cp	#ff		; Aquí se podría mirar solo el bit 7? 0=ready
 	ccf
 	ret	nc
 
@@ -2148,6 +2163,50 @@ PRINT:
 ;-----------------------------------------------------------------------------
 		include	"romdisk.asm"
 
+;-----------------------------------------------------------------------------
+; Restore screen parameters on MSX>=2 if they're not set yet
+;-----------------------------------------------------------------------------
+USRSCRSET:
+	ld	a,(MSXVER)
+	or	a
+	jr	nz,.notMSX1
+
+.MSX1:
+	ld	a,(SCRMOD)
+	or	a
+	ret
+	jp	INITXT
+
+.notMSX1:
+	ld	c,23h
+	ld 	ix,REDCLK
+	call	EXTROM
+	and	1
+	ld	b,a
+	ld	a,(SCRMOD)
+	cp	b
+	jr	nz,.restore
+	inc	c
+	ld 	ix,REDCLK
+	call	EXTROM
+	ld	b,a
+	inc	c
+	ld 	ix,REDCLK
+	call	EXTROM
+	add	a,a
+	add	a,a
+	add	a,a
+	add	a,a
+	or	b
+	ld	b,a
+	ld	a,(LINLEN)
+	cp	b
+	ret	z
+.restore:
+	xor	a
+	ld	ix,SDFSCR
+	jp	EXTROM
+
 ;-----------------------------------------------------------------------------
 ; Strings
 ;-----------------------------------------------------------------------------
@@ -2159,24 +2218,25 @@ endm
 TXT_INFO:
 		db	"MegaFlashROM SCC+ SD driver",13,10
 		VERSION_STRING %DRIVER_VERSION,%DRIVER_SUBVERSION
-		db	"(c) Manuel Pazos 2013",13,10
+		db	"(c) 2013 Manuel Pazos",13,10
 TXT_EMPTY:		
 		db	13,10,0
 
 TXT_INIT:
-		db	"SD card slot ",0
+		db	"SD Card slot ",0
 
 TXT_ROMDSKOK:
-		db	"ROM disk found.",13,10,0
+		db	"ROM Disk found.",13,10
+		db	13,10,0
 
 TXT_MMC:
-		db	"MMC",13,10,0
+		db	" MMC",13,10,0
 TXT_SD1x:
-		db	"SDSC 1.x",13,10,0
+		db	" SDSC 1.x",13,10,0
 TXT_SD2x:
-		db	"SDSC 2.x",13,10,0
+		db	" SDSC 2.x",13,10,0
 TXT_SDHC:
-		db	"SDHC",13,10,0
+		db	" SDHC",13,10,0
 	
 IDX_TYPE:
 		dw	TXT_MMC