From edbe7d0781f721af53b42160b84a8071597d7a40 Mon Sep 17 00:00:00 2001
From: Wayne Warthen <wwarthen@gmail.com>
Date: Wed, 6 Dec 2023 19:37:02 -0800
Subject: [PATCH] Improved BPBIOS Bank Id Management

---
 Source/BPBIOS/hbios.z80   | 21 ++++++++++-----------
 Source/BPBIOS/ibmv-ww.z80 | 24 +++++++++++++++++++++---
 Source/BPBIOS/romwbw.lib  | 27 ++++++++++++++++-----------
 Source/Images/Build.cmd   |  4 ++++
 4 files changed, 51 insertions(+), 25 deletions(-)

diff --git a/Source/BPBIOS/hbios.z80 b/Source/BPBIOS/hbios.z80
index 0a97670d..9c9e7ecb 100644
--- a/Source/BPBIOS/hbios.z80
+++ b/Source/BPBIOS/hbios.z80
@@ -43,18 +43,15 @@ HBX_CPYLEN	EQU	0FFE8H
 ; call here, make required changes, then update the
 ; BIOSJT to point directly to the normal SELMEM routine for
 ; all subsequent calls.
+;
+; HBIOS bank ids are computed by subtracting the BPBIOS bank id
+; from the ending HBIOS bank id.  HBIOS RAM bank ids start at 80h.
+; The ending HBIOS bank id (HB_BNKEND) is (80h + RAM banks).  Since
+; the number of RAM banks in a system can vary, HB_BNKEND is
+; determined here at startup.
+;
+; See romwbw.lib for additional RAM bank layout information.
 
-	; BPBIOS	HBIOS		Typical
-	; ------------	--------------	--------------
-	;  -1: <COMMON>	BID_COM		90h - 1 = 8Fh
-	;  -2: TPABNK	BID_USR         90h - 2 = 8Eh
-	;  -3: SYSBNK	BID_SYS		90h - 3 = 8Dh
-	;  -4: RAMBNK	BID_BUF		90h - 4 = 8Ch
-	;  -4: MAXBNK	BID_BUF		90h - 4 = 8Ch
-	;  -5:		BID_RAMM	90h - 5 = 8BH
-	; -15:		BID_RAMD	90h - 15 = 81h (varies w/ memory size)
-	; -16:		BID_HB		90h - 16 = 80h (varies w/ memory size)
-	
 HB_SELMEM:
 	PUSH	AF
 	PUSH	BC
@@ -103,9 +100,11 @@ HB_MOVE:
 	PUSH	HL
 	LD	HL,HB_BNKEND
 	LD	A,(HB_SRCBNK)
+	NEG
 	ADD	A,(HL)		; Adjust for HBIOS bank ids
 	LD	(HBX_SRCBNK),A
 	LD	A,(HB_DSTBNK)
+	NEG
 	ADD	A,(HL)		; Adjust for HBIOS bank ids
 	LD	(HBX_DSTBNK),A
 	POP	HL
diff --git a/Source/BPBIOS/ibmv-ww.z80 b/Source/BPBIOS/ibmv-ww.z80
index 2c984758..bcf30bb3 100644
--- a/Source/BPBIOS/ibmv-ww.z80
+++ b/Source/BPBIOS/ibmv-ww.z80
@@ -115,10 +115,24 @@ SELMEM:	LD	(USRBNK),A	; Update user bank
 ;  Must preserve all Registers including Flags.
 ;  All Bank Switching MUST be done by this routine
 ;::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+;
+; Parameter to BNKADJ (ADD) is set dynamically at initialization.
 
 SELBNK:	PUSH	AF		; Save regs
 SELBN0:	LD	(CURBNK),A	; Save as current bank #
-BNKADJ:	ADD	A,90H		; Adjust for HBIOS bank ids
+	NEG
+BNKADJ:	ADD	A,0FFH		; Adjust for HBIOS bank ids
+
+	  IF HB_DEBUG AND FALSE
+
+	CALL	PRTSTRD
+	DEFB	'[SELBNK: $'
+	CALL	PRTHEXBYTE
+	CALL	PRTSTRD
+	DEFB	']$'
+
+	  ENDIF
+
 	CALL	HBX_BNKSEL
 	POP	AF		; restore regs
 	RET
@@ -172,7 +186,9 @@ FRGETB:
 	PUSH	BC		; Save BC
 	PUSH	DE		; Save DE
 	LD	B,0FAH		; HBIOS Peek function
-	LD	D,C		; Bank in D
+	LD	A,(HB_BNKEND)	; Adjust BP bank id
+	SUB	C		; ... to HBIOS bank id
+	LD	D,A		; Put in D
 	CALL	HBX_INVOKE	; Do it
 	LD	A,E		; Value to A
 	POP	DE		; Restore DE
@@ -203,8 +219,10 @@ FRPUTB:
 	PUSH	BC		; Save BC
 	PUSH	DE		; Save DE
 	LD	B,0FBH		; HBIOS Poke function
-	LD	D,C		; Bank in D
 	LD	E,A		; Value in E
+	LD	A,(HB_BNKEND)	; Adjust BP bank id
+	SUB	C		; ... to HBIOS bank id
+	LD	D,A		; Put in D
 	CALL	HBX_INVOKE	; Do it
 	POP	DE		; Restore DE
 	POP	BC		; Restore BC
diff --git a/Source/BPBIOS/romwbw.lib b/Source/BPBIOS/romwbw.lib
index ff9febb4..c0b846df 100644
--- a/Source/BPBIOS/romwbw.lib
+++ b/Source/BPBIOS/romwbw.lib
@@ -48,21 +48,26 @@ DRV_P		SET	NO		; YES if system has flopy drives
 ;
 ; RAM/ROM Bank Reserve
 ;
-HB_RAMRESV	EQU	5		; RAM reserve is 8 banks
+HB_RAMRESV	EQU	5		; RAM reserve is 5 banks
 HB_ROMRESV	EQU	4		; ROM reserve is 4 banks
 ;
 ; Layout of RAM banks
 ;
-; TODO: Query system via HBIOS API to determine the actual bank
-; assignments, then adjust BPBIOS operation accordingly.
-;
-BID_HB		EQU	-16	; 90h - 16 = 80h
-BID_RAMD	EQU	-15	; 90h - 15 = 81h
-BID_RAMM	EQU	-5	; 90h - 5 = 8Bh
-BID_BUF		EQU	-4	; 90h - 4 = 8Ch
-BID_SYS		EQU	-3	; 90h - 3 = 8Dh
-BID_USR		EQU	-2	; 90h - 2 = 8Eh
-BID_COM		EQU	-1	; 90h - 1 = 8Fh
+; These are BPBIOS bank ids.  They map to HBIOS bank ids
+; by subtracting from the ending HBIOS bank id (N).  HBIOS RAM bank ids
+; start at 80h.  The ending HBIOS bank id is (80h + RAM banks).  The
+; typical layout assumes 16 banks of RAM starting at HBIOS bank id 80h
+; and ending at bank id 90h (N = 90h).
+;
+; BPBIOS						HBIOS (TYPICAL)
+; ----------------------------------------------	---------------
+; <HBIOS>						80h   (80h)
+; <RAMD>						81h   (81h)
+; <RAMM>						N - 5 (8Bh)
+BID_BUF		EQU	4	; BNK3 -> RAMBNK	N - 4 (8Ch)
+BID_SYS		EQU	3	; BNK2 -> SYSBNK	N - 3 (8Dh)		
+BID_USR		EQU	2	; BNK0 -> TPABNK	N - 2 (8Eh)		
+BID_COM		EQU	1	; BNK1 ->		N - 1 (8Fh)		
 ;
 HB_EI	MACRO
 	EI
diff --git a/Source/Images/Build.cmd b/Source/Images/Build.cmd
index 42e6757a..b28ecc3a 100644
--- a/Source/Images/Build.cmd
+++ b/Source/Images/Build.cmd
@@ -1,6 +1,10 @@
 @echo off
 setlocal
 
+:: call BuildDisk.cmd bp hd wbw_hd1k
+:: copy /b hd1k_prefix.dat + ..\..\Binary\hd1k_bp.img + ..\..\Binary\hd1k_cpm22.img + ..\..\Binary\hd1k_zsdos.img + ..\..\Binary\hd1k_nzcom.img + ..\..\Binary\hd1k_cpm3.img + ..\..\Binary\hd1k_zpm3.img + ..\..\Binary\hd1k_ws4.img ..\..\Binary\hd1k_combo_bp.img || exit /b
+:: goto :eof
+
 echo.
 echo Building Floppy Disk Images...
 echo.