From a1be61427985524e931b086bcac171b189f08561 Mon Sep 17 00:00:00 2001
From: Wayne Warthen <wwarthen@gmail.com>
Date: Mon, 4 May 2020 13:34:36 -0700
Subject: [PATCH] Cleanup

---
 Source/CBIOS/cbios.asm  | 105 ++++++++++++++++++++++++++--------------
 Source/CPM3/diskio.z80  |   2 +-
 Source/HBIOS/romldr.asm |   1 -
 3 files changed, 71 insertions(+), 37 deletions(-)

diff --git a/Source/CBIOS/cbios.asm b/Source/CBIOS/cbios.asm
index 805a43bc..7e24d981 100644
--- a/Source/CBIOS/cbios.asm
+++ b/Source/CBIOS/cbios.asm
@@ -1247,6 +1247,10 @@ DSK_SELECT:
 	LD	HL,0		; ZERO
 	LD	(SEKLBA),HL	; CLEAR FIRST WORD
 	LD	(SEKLBA+2),HL	; CLEAR SECOND WORD
+;
+	; SET LEGACY SECTORS PER SLICE
+	LD	HL,16640	; LEGACY SECTORS PER SLICE
+	LD	(SPS),HL	; SAVE IT
 ;
 	; CHECK MBR OF PHYSICAL DISK BEING SELECTED
 	; WILL UPDATE MEDID AND LBAOFF IF VALID CP/M PARTITION EXISTS
@@ -1273,7 +1277,7 @@ DSK_SELECT:
 	INC	HL		; BUMP TO MSB
 	LD	(HL),D		; SET MSB OF DPB IN DPH
 ;
-;	; PLUG LBA OFFSET INTO ACTIVE DPH
+	; PLUG LBA OFFSET INTO ACTIVE DPH
 	LD	HL,(SEKDPH)	; POINT TO START OF DPH
 	LD	BC,16		; OFFSET OF LBA OFFSET IN DPH
 	ADD	HL,BC		; HL := DPH.LBAOFF PTR
@@ -1364,6 +1368,9 @@ DSK_MBR3:
 	LD	DE,SEKLBA	; LOC TO STORE LBA OFFSET
 	LD	BC,4		; 4 BYTES (32 BITS)
 	LDIR			; COPY IT
+	; IF BOOT FROM PARTITION, USE NEW SECTORS PER SLICE VALUE
+	LD	HL,16384		; NEW SECTORS PER SLICE
+	LD	(SPS),HL		; SAVE IT
 ;
 DSK_MBR4:
 	; RESTORE BANK
@@ -1371,46 +1378,73 @@ DSK_MBR4:
 	CALL	HB_BNKSEL	; SELECT IT
 ;
 DSK_MBR5:
-;
-	; DIFFERENT ALGORITHM FOR NEW HD FORMAT
-	LD	A,(MEDID)	; GET MEDIA ID
-	CP	MID_HDNEW	; NEW FORMAT?
-	JR	Z,DSK_MBR6	; IF SO, GO THERE
-;
-	; OLD HD FORMAT, 65 TRACKS PER SLICE
-	LD	A,(SLICE)	; GET SLICE
-	LD	E,A		; E = SLICE NO
-	LD	H,65		; H = TRACKS PER SLICE
-	CALL	MULT8		; HL := H * E (TOTAL TRACK OFFSET)
-	LD	DE,0		; CLEAR HI WORD
-	LD	B,8		; 16 SPT, SHIFT 4 BITS
-	CALL	RL32		; DO IT
-	JR	DSK_MBR7	; DONE
-;
-DSK_MBR6:
-	; NEW HD FORMAT, MULTIPLY SLICE BY 8MB
-	LD	DE,0		; CLEAR HIWORD
-	LD	H,0		; CLEAR HI BYTE OR LOWORD
-	LD	A,(SLICE)	; GET SLICE
-	LD	L,A		; PUT SLICE IN LOW BYTE
-	LD	B,14
-	CALL	RL32		; MULTIPLY BY 16384 SECTORS (8MB)
-;
-DSK_MBR7:
-	; ADD IN LBA OFFSET
-	LD	BC,(SEKLBA)	; LBA OFFSET LOWORD
-	ADD	HL,BC
-	EX	DE,HL
-	LD	BC,(SEKLBA+2)	; LBA OFFSET HIWORD
-	ADC	HL,BC
-	EX	DE,HL
-	SET	7,D		; SET LBA ACCESS BIT
+	; ADJUST LBA OFFSET BASED ON TARGET SLICE
+	LD	A,(SLICE)		; GET SLICE, A IS LOOP CNT
+	LD	HL,(SEKLBA)		; SET DE:HL
+	LD	DE,(SEKLBA+2)		; ... TO STARTING LBA
+	LD	BC,(SPS)		; SECTORS PER SLICE
+BOOT6:
+	OR	A			; SET FLAGS TO CHECK LOOP CNTR
+	JR	Z,BOOT8			; DONE IF COUNTER EXHAUSTED
+	ADD	HL,BC			; ADD ONE SLICE TO LOW WORD
+	JR	NC,BOOT7		; CHECK FOR CARRY
+	INC	DE			; IF SO, BUMP HIGH WORD
+BOOT7:
+	DEC	A			; DEC LOOP DOWNCOUNTER
+	JR	BOOT6			; AND LOOP
+BOOT8:
+	LD	(LBA),HL		; SAVE NEW LBA, LOW WORD
+	LD	(LBA+2),DE		; SAVE NEW LBA, HIGH WORD
 	; RESAVE IT
 	LD	(SEKLBA),HL	; LOWORD
 	LD	(SEKLBA+2),DE	; HIWORD
 	; SUCCESSFUL FINISH
 	XOR	A		; SUCCESS
 	RET			; DONE
+
+
+
+
+
+;	; DIFFERENT ALGORITHM FOR NEW HD FORMAT
+;	LD	A,(MEDID)	; GET MEDIA ID
+;	CP	MID_HDNEW	; NEW FORMAT?
+;	JR	Z,DSK_MBR6	; IF SO, GO THERE
+;;
+;	; OLD HD FORMAT, 65 TRACKS PER SLICE
+;	LD	A,(SLICE)	; GET SLICE
+;	LD	E,A		; E = SLICE NO
+;	LD	H,65		; H = TRACKS PER SLICE
+;	CALL	MULT8		; HL := H * E (TOTAL TRACK OFFSET)
+;	LD	DE,0		; CLEAR HI WORD
+;	LD	B,8		; 16 SPT, SHIFT 4 BITS
+;	CALL	RL32		; DO IT
+;	JR	DSK_MBR7	; DONE
+;;
+;DSK_MBR6:
+;	; NEW HD FORMAT, MULTIPLY SLICE BY 8MB
+;	LD	DE,0		; CLEAR HIWORD
+;	LD	H,0		; CLEAR HI BYTE OR LOWORD
+;	LD	A,(SLICE)	; GET SLICE
+;	LD	L,A		; PUT SLICE IN LOW BYTE
+;	LD	B,14
+;	CALL	RL32		; MULTIPLY BY 16384 SECTORS (8MB)
+;;
+;DSK_MBR7:
+;	; ADD IN LBA OFFSET
+;	LD	BC,(SEKLBA)	; LBA OFFSET LOWORD
+;	ADD	HL,BC
+;	EX	DE,HL
+;	LD	BC,(SEKLBA+2)	; LBA OFFSET HIWORD
+;	ADC	HL,BC
+;	EX	DE,HL
+;	SET	7,D		; SET LBA ACCESS BIT
+;	; RESAVE IT
+;	LD	(SEKLBA),HL	; LOWORD
+;	LD	(SEKLBA+2),DE	; HIWORD
+;	; SUCCESSFUL FINISH
+;	XOR	A		; SUCCESS
+;	RET			; DONE
 ;
 #ENDIF
 ;
@@ -1654,6 +1688,7 @@ DEFDRIVE	.DB	0		; DEFAULT DRIVE
 CCPBUF		.DW	0		; ADDRESS OF CCP BUF IN BIOS BANK
 MEDID		.DB	0		; TEMP STORAGE FOR MEDIA ID
 SLICE		.DB	0		; CURRENT SLICE
+SPS		.DW	0		; SECTORS PER SLICE
 ;
 #IFDEF PLTWBW
 BNKBIOS		.DB	0		; BIOS BANK ID
diff --git a/Source/CPM3/diskio.z80 b/Source/CPM3/diskio.z80
index 61f63900..7157619d 100644
--- a/Source/CPM3/diskio.z80
+++ b/Source/CPM3/diskio.z80
@@ -499,7 +499,7 @@ media4:
 
 media5:
 	; Adjust LBA offset based on target slice
-	ld	a,(slice)		; get boot slice, A is loop cnt
+	ld	a,(slice)		; get slice, A is loop cnt
 	ld	hl,(lba)		; set DE:HL
 	ld	de,(lba+2)		; ... to starting LBA
 	ld	bc,(sps)		; sectors per slice
diff --git a/Source/HBIOS/romldr.asm b/Source/HBIOS/romldr.asm
index 0abb1668..2bf562ad 100644
--- a/Source/HBIOS/romldr.asm
+++ b/Source/HBIOS/romldr.asm
@@ -632,7 +632,6 @@ diskboot:
 #if (BIOS == BIOS_WBW)
 ;
 	; Check that drive actually exists
-	;ld	c,a			; put in C for func call
 	ld	b,BF_SYSGET		; HBIOS func: sys get
 	ld	c,BF_SYSGET_DIOCNT	; HBIOS sub-func: disk count
 	rst	08			; do it, E=disk count