46 lines
755 B
ArmAsm
46 lines
755 B
ArmAsm
// #LAYOUT# STD * #TAKE
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// #LAYOUT# * KERNAL_0 #TAKE
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// #LAYOUT# * * #IGNORE
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//
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// Tape (turbo) helper routine - synchronization handling
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//
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// .Y should contain start value (either $89 or $09)
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// Carry set = failed
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#if CONFIG_TAPE_NORMAL
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tape_normal_sync:
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lda #$06
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sta VIC_EXTCOL
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// Injest bytes of decreasing values
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jsr tape_normal_get_marker_while_sync
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bcs tape_normal_sync_fail // branch if end of data marker
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jsr tape_normal_get_byte
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bcs tape_normal_sync_fail
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cpy INBIT // INBIT contains same value as .A
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bne tape_normal_sync_fail
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dey
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and #%01111110
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bne tape_normal_sync // branch if not $80 and not $00
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clc
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rts
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tape_normal_sync_fail:
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sec
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rts
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#endif
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