FeralChild64
d489e7bf41
commit 2f27e29758da1f1ec965588c0712125051a6f71a Merge: ba722b1796b62fAuthor: FeralChild64 <you@example.com> Date: Tue Jan 28 17:34:53 2020 +0100 Merge branch 'master' into tape_redirect commit ba722b17e627af7dd067932688de0a3d86423e37 Author: FeralChild64 <you@example.com> Date: Tue Jan 28 17:28:19 2020 +0100 finished Mega65 variant of tape routines commit 47de685f2e08576504c5e00a5b7cb78498d22e72 Author: FeralChild64 <you@example.com> Date: Mon Jan 27 23:06:45 2020 +0100 compilation fix commit c3641acec049a7a6b53c35795b1f9e2df212cec2 Author: FeralChild64 <you@example.com> Date: Mon Jan 27 22:53:30 2020 +0100 dependencies fix commit dfad7a30bde043fa077005624dde1de4b72573b6 Merge: e4b0ec9e410bc0Author: FeralChild64 <you@example.com> Date: Mon Jan 27 21:25:49 2020 +0100 Merge branch 'master' into tape_redirect commit e4b0ec9c85861bde2ce52e0828d3bf895a681e17 Author: FeralChild64 <you@example.com> Date: Sat Jan 25 22:25:20 2020 +0100 initial attempt to move tape code to Mega65 extra ROM
78 lines
1.3 KiB
ArmAsm
78 lines
1.3 KiB
ArmAsm
// #LAYOUT# STD * #TAKE
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// #LAYOUT# M65 KERNAL_1 #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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// Based on routine by enthusi/Onslaught, found here:
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// - https://codebase64.pokefinder.org/doku.php?id=base:turbotape_loader_source
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#if CONFIG_TAPE_TURBO
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tape_turbo_sync_header:
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// Initial pulse threshold
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lda #$BF // measured 128 bits '0' and 128 bits '1' under VICE, calculated average
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sta __pulse_threshold
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// Synchronize with start of sync sequence
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jsr tape_turbo_sync_first
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#if CONFIG_TAPE_AUTODETECT
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bcs tape_turbo_sync_done
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#endif
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// Perform synchronization, double loop, total $C0 * $04 iterations
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ldx #$C0
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!:
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ldy #$04
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!:
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stx XSAV
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jsr tape_turbo_get_byte
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cmp #$02
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bne tape_turbo_sync_header // branch if failure
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dey
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bne !-
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ldx XSAV
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dex
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bne !--
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// FALLTROUGH
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tape_turbo_sync_payload:
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jsr tape_turbo_sync_first
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#if CONFIG_TAPE_AUTODETECT
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bcs tape_turbo_sync_done // this shopuld not happen
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#endif
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!:
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ldx #$09 // 9, 8, ...
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!:
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jsr tape_turbo_get_byte
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cmp #$02
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beq !-
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ldy #$00
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!:
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cpx INBIT
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bne tape_turbo_sync_payload
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jsr tape_turbo_get_byte
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dex
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bne !-
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#if CONFIG_TAPE_AUTODETECT
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clc
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#endif
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// FALLTROUGH
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tape_turbo_sync_done:
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rts
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#endif // CONFIG_TAPE_TURBO
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