Support Font Data in ROM

Video soft font data was occupying a large amount of space in the HBIOS bank.  This change moves the font data to a ROM bank by default.

Thanks and credit to @b1ackmai1er who provided much of the code that originated this change.

Co-Authored-By: b1ackmai1er <39449559+b1ackmai1er@users.noreply.github.com>

Source/HBIOS/hbios.asm

@@ -5454,7 +5454,7 @@ SYS_RESUSER:
 ;
 	IN0	A,(Z180_ITC)		; GET ITC REGISTER
 	XOR	$80			; PRECLEAR TRAP BIT
-	RET	M			; IF TRAP BIT NOT SET, DONE
+	JP	M,SYS_RESUSER3		; IF TRAP BIT NOT SET, DONE
 ;
 	; HANDLE INVALID OPCODE
 	DEC	HL			; BACK UP TO OPCODE START
@@ -5488,6 +5488,7 @@ SYS_RESUSER2:
 ;
 #ENDIF
 ;
+SYS_RESUSER3:
 	; RESET ACTIVE VIDEO DISPLAY ATTACHED TO EMULATOR
 	CALL	TERM_RESET
 ;
@@ -8287,62 +8288,111 @@ HB_CPUSPD2:
 	RET				; AND DONE
 #ENDIF ; CPUFAM != CPU_EZ80
 ;
-HB_UTIL_END	.EQU	$
-;
 ;==================================================================================================
 ; FONT MANAGEMENT ROUTINES
 ;==================================================================================================
 ;
 ; SELECT A FONT BASED ON THE FONT ID PASSED IN REGISTER A.  THIS WILL
-; PREPARE TO STREAM FONT DATA VIA THE FNT_NEXT ROUTINE.  USES DE, AND
-; HL.
+; PREPARE TO STREAM FONT DATA VIA THE FNT_NEXT ROUTINE.  USES AF, BC,
+; DE, AND HL.  RETURNS ZERO (ZF SET) FOR SUCCESS OR NON-ZERO (ZF CLEAR)
+; IF FONT NOT FOUND.
+;
+#IF ROMFONTS
+FNT_BNKID	.EQU	FONTS_BNK
+FNT_MAP		.EQU	FONTS_LOC
+#ELSE
+FNT_BNKID	.EQU	BID_BIOS
+#ENDIF
 ;
 FNT_SELECT:
-	; THE MAP IS CURRENTLY ASSUMED TO BE IN THE HBIOS BANK
 	LD	E,A			; DESIRED FONT ID TO E
+	LD	A,FNT_BNKID		; FONT BANK ID TO A
+	LD	(FNT_BID),A		; SAVE IN WORKING VARIABLE
+	LD	D,FNT_BNKID		; D = BANK FOR FONT DATA
 	LD	HL,FNT_MAP		; POINT TO START OF MAP
-	LD	A,(HL)			; LOAD THE FONT ID
-	AND	$7F			; REMOVE COMPRESSION BIT 7
-	OR	A			; CHECK OF END OF TABLE
+FNT_SELECT0:
+	CALL	FNT_BYTE		; LOAD THE FONT ID FROM MAP
+	;;;CALL	PC_SPACE		; ** DEBUG ***
+	;;;CALL	PRTHEXBYTE		; ** DEBUG ***
+	AND	$7F			; MASK OUT COMP INDICATOR
+	OR	A			; CHECK FOR END OF TABLE
 	JR	Z,FNT_SELECT_ERR	; IF SO, BAIL OUT W/ ERR
 	CP	E			; CHECK FOR DESIRED FONT ID
 	JR	Z,FNT_SELECT1		; IF SO, LOCK IT IN
 	INC	HL			; BUMP PAST FONT ID
 	INC	HL			; BUMP TO
 	INC	HL			; ... NEXT TABLE ENTRY
-	JR	FNT_SELECT		; AND LOOP
+	JR	FNT_SELECT0		; AND LOOP
 ;
 FNT_SELECT1:
-	LD	E,(HL)			; GET FONT ID BYTE
+	CALL	FNT_BYTE		; GET FONT ID BYTE
+	PUSH	AF			; SAVE IT
+	LD	C,A			; SAVE IT IN E
 	INC	HL			; BUMP PAST FONT ID
-	LD	A,BID_BIOS		; FOR NOW, ASSUME FONT IN HBIOS
-	LD	(FNT_BID),A		; SAVE IT
-	LD	A,(HL)			; DEREF HL
-	INC	HL
-	LD	H,(HL)
-	LD	L,A
-	BIT	7,E			; COMPRESSED FONT DATA?
+	CALL	FNT_BYTE		; LO BYTE OF ADDRESS
+	LD	E,A			; PUT IN E
+	INC	HL			; BUMP
+	CALL	FNT_BYTE		; HI BYTE OF ADDRESS
+	LD	D,A			; PUT IN D
+	EX	DE,HL			; FULL ADDRESS TO HL
+	POP	AF			; RECOVER FONT ID
+	AND	$80			; COMPRESSED FONT DATA?
 	JR	Z,FNT_SELECT2		; IF NOT, SKIP DECOMP
 ;
 #IF ((CVDUENABLE | GDCENABLE | TMSENABLE | VGAENABLE | VRCENABLE) & USELZSA2)
-	; BELOW DOES NOT YET HANDLE COMPRESSED FONT DATA IN ROM!!!
-	PUSH	HL			; SAVE COMP DATA PTR
-	LD	HL,0			; COPY SP
-	ADD	HL,SP			; ... TO HL
-	LD	DE,$2100		; SPACE FOR DECOMP BUF AND STACK
-	CCF				; CLEAR CARRY
-	SBC	HL,DE			; HL IS START OF DECOMP BUF
-	POP	DE			; RECOVER COMP DATA PTR
-	EX	DE,HL			; SWAP
-	PUSH	DE			; SAVE START OF DECOMP BUF
-	CALL	DLZSA2			; DECOMP
-	POP	HL			; START OF DECOMP BUF
+;
+; DECOMPRESS THE FONT DATA.  WE USURP $E000-$EFFF AS A BUFFER FOR THE
+; DECOMPRESSED DATA.  IF THE FONT DATA IS IN ROM, WE FIRST COPY THE
+; COMPRESSED DATA TO $D000-DFFF.  THE BUFFER SIZES ARE LARGE ENOUGH TO
+; CONTAIN THE LARGEST FONT IN ITS DECOMPRESSED STATE.  THE BUFFER
+; LOCATIONS ARE SAFE DURING BOOT, BUT *NOT* FOR A RUNNING SYSTEM.  SO,
+; ANY FONT THAT MUST BE RELOADED AFTER BOOT WILL NEED TO BE SAVED IN
+; DECOMPRESSED STATE!  SPECIFICALLY THE 6X8 TMS FONT.
+;
+	;;;CALL	PC_SPACE		; ** DEBUG ***
+	;;;LD	A,'C'                   ; ** DEBUG ***
+	;;;CALL	COUT                    ; ** DEBUG ***
+;
+  #IF ROMFONTS
+	;;;LD	A,'R'			; ** DEBUG ***
+	;;;CALL	COUT                    ; ** DEBUG ***
+; 
+	; COPY THE COMPRESSED DATA FROM ROM TO RAM BUFFER
+	LD	A,(FNT_BID)		; GET ROM FONT BANK ID
+	LD	(HB_SRCBNK),A		; SETUP SOURCE BANK
+	LD	A,BID_BIOS		; DEST BANK IS BIOS BANK
+	LD	(HB_DSTBNK),A		; SETUP DESTINATION BANK
+	LD	DE,$D000		; PUT DEST IN DE
+	LD	BC,$1000		; BLINDLY COPY 4K
+	CALL	HBX_BNKCPY		; COPY COMP FONT DATA TO RAM
+;
+	; DO THE DECOMPRESSION
+	LD	HL,$D000		; COMP BUF ADR TO HL
+	LD	DE,$E000		; DECOMP BUF ADR TO DE
+	CALL	DLZSA2			; DECOMPRESS
+	LD	A,BID_BIOS		; BANK OF DECOMP BUF
+	LD	(FNT_BID),A		; UPDATE FNT_BID
+	LD	HL,$E000		; DEOMP BUF ADR TO HL
+  #ELSE
+	;;;LD	A,'I'			; ** DEBUG ***
+	;;;CALL	COUT			; ** DEBUG ***
+	LD	DE,$E000		; DECOMP BUF ADR TO DE
+	CALL	DLZSA2			; DECOMPRESS
+	LD	HL,$E000		; DECOMP BUF ADR TO HL
+  #ENDIF
+;
 #ELSE
 	JR	FNT_SELECT_ERR		; OOPS, CAN'T DECOMPRESS
 #ENDIF
 ;
 FNT_SELECT2:
 	LD	(FNT_PTR),HL		; SAVE STARTING POINTER
+	;;;LD	A,(FNT_BID)		; ** DEBUG ***
+	;;;CALL	PC_SPACE                ; ** DEBUG ***
+	;;;CALL	PRTHEXBYTE              ; ** DEBUG ***
+	;;;LD	HL,(FNT_PTR)            ; ** DEBUG ***
+	;;;CALL	PC_SPACE                ; ** DEBUG ***
+	;;;CALL	PRTHEXWORDHL            ; ** DEBUG ***
 	XOR	A			; SIGNAL SUCCESS
 	RET
 
@@ -8352,41 +8402,38 @@ FNT_SELECT_ERR:
 ;
 ; RETURN THE NEXT BYTE OF FONT DATA IN REGISTER A.  EACH CALL RETURNS
 ; THE NEXT BYTE OF DATA.  THERE IS NO INDICATION OF THE END OF THE
-; FONT DATA.  THE CALLER IS EXPECTED TO KNOW HOW MANY
-; BYTES OF FONT DATA WILL BE RETURNED.  ONLY REGISTER A IS
-; MODIFIED.
-;
-ROMFONTS	.EQU	TRUE
+; FONT DATA.  THE CALLER CONTROLS NUMBER OF BYTES REQUESTED.
+; ONLY REGISTER A IS MODIFIED.
 ;
 FNT_NEXT:
-#IF ROMFONTS
 	PUSH	HL
+	LD	HL,(FNT_PTR)
+	CALL	FNT_BYTE
+	INC	HL
+	LD	(FNT_PTR),HL
+	POP	HL
+	RET
+;
+; HELPER FUNCTION TO RETRIEVE A BYTE OF ROM FONT DATA FROM THE
+; ROM FONT BANK.  RETURNS BYTE FROM (FNT_BID:HL).  RETURNS BYTE IN A.
+; ALL OTHER REGSITERS UNCHANGED.
+;
+FNT_BYTE:
 	PUSH	DE
 	LD	A,(FNT_BID)
 	LD	D,A
-	LD	HL,(FNT_PTR)
 	HB_DI
 	CALL	HBX_PEEK
 	HB_EI
-	INC	HL
-	LD	(FNT_PTR),HL
 	LD	A,E
 	POP	DE
-	POP	HL
 	RET
-#ELSE
-	PUSH	HL			; SAVE HL
-	LD	HL,(FNT_PTR)		; GET CUR FONT DATA PTR
-	LD	A,(HL)			; GET NEXT BYTE TO A
-	INC	HL			; BUMP PTR
-	LD	(FNT_PTR),HL		; SAVE PTR
-	POP	HL			; RESTORE HL
-	RET				; DONE
-#ENDIF
 ;
 FNT_BID		.DB	0		; BANK CONTAINING FONT DATA
 FNT_PTR		.DW	0		; POINTER TO NEXT BYTE OF DATA
 ;
+HB_UTIL_END	.EQU	$
+;
 ;==================================================================================================
 ; DISPLAY SUMMARY OF ATTACHED UNITS/DEVICES
 ;==================================================================================================
@@ -9604,85 +9651,88 @@ ORG_FONTS	.EQU	$
 ;
 	MEMECHO	"FONTS"
 ;
-#IFDEF USEFONT6X8
-FONT6X8:
-;
-; FOR NOW, WE NEVER COMPRESS THE 6X8 FONT.  SEE TMS DRIVER.
-;
-  #IF USELZSA2 & FALSE
-    #INCLUDE "font6x8c.asm"
-  #ELSE
-    #INCLUDE "font6x8u.asm"
-  #ENDIF
-	MEMECHO	" 6X8"
-#ENDIF
-;
-#IFDEF USEFONT8X8
-FONT8X8:
-;
-  #IF USELZSA2
-    #INCLUDE "font8x8c.asm"
-  #ELSE
-    #INCLUDE "font8x8u.asm"
-  #ENDIF
-	MEMECHO	" 8X8"
-#ENDIF
-;
-#IFDEF USEFONT8X11
-FONT8X11:
-  #IF USELZSA2
-    #INCLUDE "font8x11c.asm"
-  #ELSE
-    #INCLUDE "font8x11u.asm"
-  #ENDIF
-	MEMECHO	" 8X11"
-#ENDIF
-;
-#IFDEF USEFONT8X16
-FONT8X16:
-  #IF USELZSA2
-    #INCLUDE "font8x16c.asm"
-  #ELSE
-    #INCLUDE "font8x16u.asm"
-  #ENDIF
-	MEMECHO	" 8X16"
-#ENDIF
+#IF !ROMFONTS
 ;
 ; HIGH BIT OF THE FONTID BYTE INDICATES THAT THE FONT DATA IS COMPRESSED
 ;
-#IF USELZSA2
+  #IF USELZSA2
 FNT_CMPMASK	.EQU	$80
-#ELSE
+  #ELSE
 FNT_CMPMASK	.EQU	$00
-#ENDIF
+  #ENDIF
 ;
 ; FONT LOCATION MAP
 ;
 FNT_MAP:
-#IFDEF USEFONT6X8
+  #IFDEF USEFONT6X8
 	; FOR NOW, WE NEVER COMPRESS THE 6X8 FONT.  SEE TMS DRIVER.
 ;;;	.DB	FONTID_6X8 | FNT_CMPMASK
 	.DB	FONTID_6X8
 	.DW	FONT6X8
-#ENDIF
+  #ENDIF
 ;
-#IFDEF USEFONT8X8
+  #IFDEF USEFONT8X8
 	.DB	FONTID_8X8 | FNT_CMPMASK
 	.DW	FONT8X8
-#ENDIF
+  #ENDIF
 ;
-#IFDEF USEFONT8X11
+  #IFDEF USEFONT8X11
 	.DB	FONTID_8X11 | FNT_CMPMASK
 	.DW	FONT8X11
-#ENDIF
+  #ENDIF
 ;
-#IFDEF USEFONT8X16
+  #IFDEF USEFONT8X16
 	.DB	FONTID_8X16 | FNT_CMPMASK
 	.DW	FONT8X16
-#ENDIF
+  #ENDIF
 ;
 	.DB	0		; END OF TABLE
-
+;
+  #IFDEF USEFONT6X8
+FONT6X8:
+;
+; FOR NOW, WE NEVER COMPRESS THE 6X8 FONT.  SEE TMS DRIVER.
+;
+    #IF USELZSA2 & FALSE
+      #INCLUDE "font6x8c.asm"
+    #ELSE
+      #INCLUDE "font6x8u.asm"
+    #ENDIF
+	MEMECHO	" 6X8"
+  #ENDIF
+;
+  #IFDEF USEFONT8X8
+FONT8X8:
+;
+    #IF USELZSA2
+      #INCLUDE "font8x8c.asm"
+    #ELSE
+      #INCLUDE "font8x8u.asm"
+    #ENDIF
+	MEMECHO	" 8X8"
+  #ENDIF
+;
+  #IFDEF USEFONT8X11
+FONT8X11:
+    #IF USELZSA2
+      #INCLUDE "font8x11c.asm"
+    #ELSE
+      #INCLUDE "font8x11u.asm"
+    #ENDIF
+	MEMECHO	" 8X11"
+  #ENDIF
+;
+  #IFDEF USEFONT8X16
+FONT8X16:
+    #IF USELZSA2
+      #INCLUDE "font8x16c.asm"
+    #ELSE
+      #INCLUDE "font8x16u.asm"
+    #ENDIF
+	MEMECHO	" 8X16"
+  #ENDIF
+;
+#ENDIF
 ;
 SIZ_FONTS	.EQU	$ - ORG_FONTS
 		MEMECHO	" occupy "