5X: the Merlin fix

notes/rom5_zeros.txt

@@ -2,16 +2,15 @@ Inventory of zeros of 5 bytes or more in the IIc Plus ROM
 
 Main Bank
 C1FB - 5 bytes
-C4EE - 12 bytes
+C4EE - 12 bytes - delete key fix
 C5F3 - 5 bytes
-C6FB - 5 bytes
-C9A1 - 9 bytes
+C6FB - 5 bytes - but Disk II ID here at C6FF
+C9A1 - 9 bytes - beep merlin fix part 2
 CFF9 - 7 bytes - ROM 5X switcher
 
 Aux Bank
 C572 - 8 bytes
-C7FB - 8 bytes
-C7FC - 7 bytes
+C7FC - 7 bytes - ROM 5X dispatch jump at $C7FF
 CE00 - 512 bytes not usable (MIG space)
 D3B5 - 75 bytes - Accelerator menu text
 D516 - 234 bytes - ROM 5X boot

rom5x/B0_C2FC_fix_merlin_1.s

@@ -0,0 +1,8 @@
+; Code to fix merlin incompatibility with the beep patch
+; this arises because switching to the aux firmware messes up the
+; memory map slightly.  The IIc Plus WAIT routine has a fix, we adopt it here.
+.code
+.pc02
+            .org $c2fc
+            phx
+            jmp   $c9a1     ; next step

rom5x/B0_C7FC_5x_switch.s

@@ -0,0 +1,10 @@
+; There's a bit of luck in the IIc Plus firmware
+; there are 4 $00 bytes at $C7FC in the main bank, of which the last
+; is "AppleTalk version" according to the ROM $03 source code
+; in the tech ref, and should be left at $00.
+; There are also 7 $00 bytes at $C7FC in the aux bank.  So if we switch at
+; $C7FC, then we get a 4 bytes in the aux bank, just enough for a jump.
+.code
+	.org $c7fc
+	sta $c028
+

rom5x/B0_C9A1_fix_merlin_2.s

@@ -0,0 +1,7 @@
+; see B0 C2FC patch for commentary
+.code
+.pc02
+          .org  $c9a1
+          jsr   $cfe5   ; get memory config we need to fix
+          jsr   $c7fc   ; call ROM 5X dispatch
+          jmp   $c2f5   ; fix memory, restore x, a=$00

rom5x/B0_CFF9_switch_cmd.s

@@ -10,6 +10,6 @@
 	.org $cff9 ; 7 bytes available here, but don't count on $CFFF
 	lda #$a9	; lda opcode
 	nop		; jmp/jsr $cffa does lda #$ea
-	jmp $fbdf	; jump to bell1 hijack
+	jmp $c7fc	; jump to 5X dispatcher
 ; total 6 bytes.
 

rom5x/B0_FBDF_bell1_hijack.s

@@ -1,21 +0,0 @@
-; Hijack the BELL1 monitor routine to do our bidding.
-; BELL1 implements the beep sound heard on reset or
-; Ctrl-G, etc.  It starts with
-; LDA #$40
-; JSR WAIT ; delay .1 sec
-; followed by code to actually beep the speaker
-; In our case, BELL1 always loads the accumulator with
-; a fixed number, and executes a 3-byte instruction
-; Well, it turns out that to switch banks we need
-; 3 bytes, and as luck would have it the other bank
-; is empty here.
-; So the routine on the other side is the ROM 5X
-; dispatcher. It will take what is in the accumulator
-; and use that to determine the next action.
-; Obviously, $40 should beep the speaker, anything
-; else can do whatever we want.
-
-.code
-	.org $fbdf
-	sta $c028
-

rom5x/B0_FBE6_beep_fix.s

@@ -0,0 +1,13 @@
+; Fix the beep
+; inspired by http://quinndunki.com/blondihacks/?p=2471
+; see commentary in B1 FB3C patch
+.code
+.pc02
+          .org $fbe6
+          jmp  $c2fc        ; to 5X beep with merlin fix
+          .res $fbef-*,$ea  ; fill up the rest with NOPs
+.assert * = $fbef, error, "ROM 5X beep fix alignment problem"
+; the rts at $fbef is sacred
+
+          
+          

rom5x/B1_C7FF_5x_jump.s

@@ -0,0 +1,5 @@
+; See B0 C7FC patch for description
+.code
+	.org $c7ff
+  jmp $fb3c     ; to 5X dispatch
+

rom5x/B1_D6CE_rom5x_misc.s

@@ -81,7 +81,7 @@ msg1 = *
         .byte $04,$2e,"6 Boot 5.25"
         .byte $04,$ae,"7 Accelerator"
         .byte $07,$5f,"By M.G."
-msg2:   .byte $07,$db,"ROM 5X 04/08/17"
+msg2:   .byte $07,$db,"ROM 5X 11/09/17"
         .byte $05,$ae,$00		; cursor pos in menu
 msg3:   .byte $05,$b0,"SURE? ",$00
 ; metadata to identify build conditions

rom5x/B1_DB63_reset5x.s

@@ -1,47 +1,44 @@
 .code
 .psc02
 .include "iic+.defs"
-	.org reset5x ; max 157 bytes
-	stz power2 + rx_mslot	; action = normal reset
-	lda #>(rst5xrtn-1)	; common case
-	pha
-	lda #<(rst5xrtn-1)
-	pha			; note that this stays on stack
-	asl butn1		; option (closed apple)
-	bcs ckdiag
-exitrst: jmp swrts2
+          .org reset5x ; max 157 bytes
+          stz power2 + rx_mslot	; action = normal reset
+          lda #>(rst5xrtn-1)	; common case
+          pha
+          lda #<(rst5xrtn-1)
+          pha			; note that this stays on stack
+          asl butn1		; option (closed apple)
+          bcs ckdiag
+exitrst:  jmp swrts2
 ; check to see if cmd_option (both apples) are down
-ckdiag:	bit butn0		; command (open apple)
-	bmi exitrst		; return to RESET.X
+ckdiag:   bit butn0		; command (open apple)
+          bmi exitrst		; return to RESET.X
 ; present menu because only closed apple is down
-menu:	jsr menu5x		; display menu
-	jsr gkey5x
-	cmp #$b0		; "0"
-	bne ckkey1
-	ldx #$ff		; reset stack
-	txs
-	lda #>(monitor-1)	; monitor entry on stack
-	pha
-	lda #<(monitor-1)
-	pha
-	jmp swrts2		; rts to enter monitor
-ckkey1:	cmp #$b2		; "2"
-	beq doconf
-	cmp #$b4		; "4"
-	bne ckkey2
-doconf:	jsr conf5x
-	bne menu		; go back to menu4x
-ckkey2:	cmp #$b7		; "7"
-	bne ckkey3
-	jsr $fd02		; accelerator menu
-	bra menu
-ckkey3:	sec
-	sbc #$b0		; ascii->number
-	bmi menu		; < 0 not valid
-	cmp #$07		; we will use 7 for accelerator later
-	bpl menu		; > 7 not valid
-	sta power2 + rx_mslot	; for boot5x
-	stz softev + 1		; deinit coldstart
-	stz pwerdup		; ditto
-	bra exitrst
+menu:     jsr menu5x		; display menu
+          jsr gkey5x
+          cmp #$b0		; "0"
+          bne ckkey1
+          ldx #$ff		; reset stack
+          txs
+          txa
+          jmp $fb3c   ; now has crash-to-monitor function
+ckkey1:   cmp #$b2		; "2"
+          beq doconf
+          cmp #$b4		; "4"
+          bne ckkey2
+doconf:   jsr conf5x
+          bne menu		; go back to menu4x
+ckkey2:   cmp #$b7		; "7"
+          bne ckkey3
+          jsr $fd02		; accelerator menu
+          bra menu
+ckkey3:   sec
+          sbc #$b0		; ascii->number
+          bmi menu		; < 0 not valid
+          cmp #$07		; we will use 7 for accelerator later
+          bpl menu		; > 7 not valid
+          sta power2 + rx_mslot	; for boot5x
+          stz softev + 1		; deinit coldstart
+          stz pwerdup		; ditto
+          bra exitrst
 

rom5x/B1_FB3C_rom5x_dispatch.s

@@ -1,45 +1,51 @@
 .code
 .psc02
 .include "iic+.defs"
-	.org $fb3c ; ~165 bytes free here
-	cmp #$a9		; reset patch
-	bne chk2
-	jmp reset5x
-chk2:	cmp #$ea		; boot patch
-	bne chk3
-	jmp boot5x
-.if newbeep
-chk3:
-.else
-chk3:	cmp #$40		; beep
-	bne dowait
+          .org  $fb3c ; ~165 bytes free here
+.proc     dispatch
+          cmp   #$a9		      ; reset patch
+          bne   :+
+          jmp   reset5x
+:         cmp   #$ea		      ; boot patch
+          bne   :+
+          jmp   boot5x
+:         cmp   #$0c
+          beq   oldbelle1
+          ; jump to monitor
+          lda   #>(monitor-1)	; monitor entry on stack as return address
+          pha
+          lda   #<(monitor-1)
+          pha
+          jmp   swrts2		    ; switch bank and rts to monitor
+.endproc
+
 ; "classic air raid beep"
-; inspired by http://quinndunki.com/blondihacks/?p=2471
-	; jsr $fcb5		; (new) WAIT for .1 sec delay
-	jsr owait
-	ldy #$c0
-obell2:	lda #$0c
-	jsr owait		; old wait for correct sound
-	lda $c030
-	dey
-	bne obell2
-	bra dexit		; back to caller
-.endif
-dowait:	jsr $fcb5		; do delay if anything else
-	lda #>($fbe2-1)		; return to other bank here (in BELL1)
-	pha			; by pushing address onto
-	lda #<($fbe2-1)		; the stack
-	pha
-	lda #$00		; in case someone assumes this
-dexit:	jmp swrts2		; back to other bank
+.proc     oldbell
+          ldy   #$c0
+obell2:	  lda   #$0c
+dowait:   jsr   oldwait	  ; old wait for correct sound, we also enter here
+          lda   $c030
+          dey
+          bne   obell2
+          jmp   swrts2
+.endproc
+; We jump into the old bell routine mid-way because it's possible for
+; someone to want to call the bell routine with a different duration
+; by putting a custom value in Y and calling fbe4 (BELL2)
+oldbelle1 := oldbell::dowait
+
 ; old wait - no ACIA access to enforce delay at
-; accelerated speeds, speaker delay tkes care of it
+; accelerated speeds, speaker delay takes care of it
 ; when we do the old beep
-owait:	sec
-owait2:	pha
-owait3: sbc #$01
-	bne owait3
-	pla
-	sbc #$01
-	bne owait2
-	rts
+.proc     oldwait
+          sec
+owait2:	  pha
+owait3:   sbc   #$01
+          bne   owait3
+          pla
+          sbc   #$01
+          bne   owait2
+          rts
+.endproc
+
+.assert * <= $fc00, error, "ROM 5X dispatch overruns $fc00"