No Slot Clock: Shave bytes and better comments
* Replace BCD->Binary with smaller routine * Replace most absolute use of $200-7 with stack * Remove unneeded sentinel byte at end of unlock sequence Leaves 9 bytes free in driver.
This commit is contained in:
Joshua Bell
parent
d9e72d3c1e
commit
1ddae4fab7
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@ -116,14 +116,14 @@ next: inc slot
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bne not_found
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bne not_found
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;; Not found in slot ROM, try main ROMs ???
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;; Not found in slot ROM, try main ROMs ???
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lda #>$C015
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lda #>$C015 ; $C015 = RDCXROM (internal or slot ROM?)
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ldy #<$C015
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ldy #<$C015
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sta ld4+2
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sta ld4+2
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sty ld4+1
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sty ld4+1
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ldy #$07
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ldy #$07 ; $C007 = INTCXROM (read internal ROM)
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sta st1+2
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sta st1+2
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sty st1+1
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sty st1+1
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dey
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dey ; $C006 = SLOTCXROM (read slot ROM)
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sta st4+2
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sta st4+2
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sty st4+1
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sty st4+1
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lda #>$C800
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lda #>$C800
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@ -277,83 +277,95 @@ loop: lda driver,y
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driver:
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driver:
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php
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php
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sei
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sei
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ld4: lda $CFFF ; self-modified
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ld4: lda $CFFF ; self-modified ($CFFF or RDCXROM)
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pha
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pha
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st1: sta $C300 ; self-modified
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st1: sta $C300 ; self-modified ($Cn00 or INTCXROM)
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ld1: lda $C304 ; self-modified
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ld1: lda $C304 ; self-modified ($Cn04)
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ldx #8
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ldx #8
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;; --------------------------------------------------
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;; Unlock the NSC by bit-banging.
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;; Unlock the NSC by bit-banging.
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uloop:
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uloop:
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unlock_addr := *+1
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unlock_addr := *+1
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lda unlock-1,x ; self-modified
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lda unlock-1,x ; self-modified (during relocation)
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sec
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sec
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ror a ; a bit at a time
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ror a ; a bit at a time
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: pha
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: pha
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lda #0
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lda #0
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rol a
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rol a
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tay
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tay
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ld2: lda $C300,y ; self-modified
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ld2: lda $C300,y ; self-modified ($Cn00)
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pla
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pla
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lsr a
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lsr a
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bne :-
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bne :-
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dex
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dex
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bne uloop
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bne uloop
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;; Read 8 bytes * 8 bits of clock data into $200...$207
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;; --------------------------------------------------
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;; Read 8 bytes * 8 bits of clock data, push onto stack
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tmp := $200
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ldx #8
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ldx #8
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bloop: ldy #8
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bloop: ldy #8
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st2:
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st2:
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: lda $C304 ; self-modified
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: lda $C304 ; self-modified ($Cn04)
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ror a
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ror a
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ror $01FF,x
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ror tmp
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dey
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dey
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bne :-
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bne :-
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lda $01FF,x ; got 8 bits
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lsr a ; BCD to binary
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;; BCD to Binary - slow but tiny
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lsr a ; shift out tens
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lda tmp ; A = value
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lsr a
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ldy #$FF ; result = -1
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lsr a
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sec
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tay
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sed
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beq donebcd
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: iny ; result += 1
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lda $01FF,x
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sbc #1 ; value -= 1
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and #$0F ; mask out units
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bcs :-
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clc
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cld
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: adc #10 ; and add tens as needed
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tya ; A = result
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dey
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bne :-
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;; Push to stack
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sta $01FF,x
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pha
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donebcd:
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dex
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dex
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bne bloop
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bne bloop
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;; Now $200...$207 is y/m/d/w/H/M/S/f
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;; --------------------------------------------------
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;; Now stack has y/m/d/w/H/M/S/F
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;; Update ProDOS date/time.
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pla ; year
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lda $0204 ; hour
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sta DATELO+1
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sta TIMELO+1
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lda $0205 ; minute
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pla ; month
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sta TIMELO
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asl
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asl
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asl
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asl
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asl
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sta DATELO
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rol DATELO+1
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lda $0201 ; month
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pla ; day
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asl a
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ora DATELO
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asl a
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asl a
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asl a
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asl a
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ora $0202 ; day
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sta DATELO
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sta DATELO
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lda $0200 ; year
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pla ; skip week
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rol a
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sta DATELO+1
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pla ; hour
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sta TIMELO+1
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pla ; minute
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sta TIMELO
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pla ; skip seconds
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pla ; skip fraction
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;; --------------------------------------------------
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;; Finish up
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pla
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pla
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bmi done
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bmi done
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st4: sta $CFFF ; self-modified
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st4: sta $CFFF ; self-modified ($CFFF or SLOTCXROM)
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done: plp
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done: plp
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rts
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rts
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@ -361,12 +373,10 @@ unlock:
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;; NSC unlock sequence
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;; NSC unlock sequence
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.byte $5C, $A3, $3A, $C5
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.byte $5C, $A3, $3A, $C5
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.byte $5C, $A3, $3A, $C5
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.byte $5C, $A3, $3A, $C5
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.byte $00
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sizeof_driver := * - driver
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sizeof_driver := * - driver
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.assert sizeof_driver <= 125, error, "Clock code must be <= 125 bytes"
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.assert sizeof_driver <= 125, error, "Clock code must be <= 125 bytes"
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;;; ************************************************************
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;;; ************************************************************
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.ifndef JUMBO_CLOCK_DRIVER
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.ifndef JUMBO_CLOCK_DRIVER
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.include "../../inc/driver_postamble.inc"
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.include "../../inc/driver_postamble.inc"
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