208 lines
3.6 KiB
ArmAsm
208 lines
3.6 KiB
ArmAsm
// #LAYOUT# STD * #TAKE
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// #LAYOUT# M65 KERNAL_0 #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 head alignemnt tool
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//
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#if CONFIG_TAPE_HEAD_ALIGN
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.label __ha_start = 3 // starting row of the chart
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.label __ha_rows = 20 // number of rows for scrolling
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// Helper tables
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.label __ha_offsets = $1000;
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.label __ha_masks = $1100;
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// Helper variables
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.label __ha_lda_addr = $1200; // 2 bytes, for code generator
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.label __ha_sta_addr = $1202; // 2 bytes, for code generator
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.label __ha_counter = $1204; // 3 bytes
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// Generated code location
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.label __ha_scroll = $1300;
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tape_head_align:
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#if (ROM_LAYOUT_M65 && SEGMENT_KERNAL_0)
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jsr map_KERNAL_1
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jsr_ind VK1__tape_head_align
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jmp map_NORMAL
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#else
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// Disable interrupts, set proper I/O values
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sei
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jsr CLALL
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jsr IOINIT
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jsr cint_legacy
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ldx #$02 // set timer A to 3 ticks
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jsr tape_common_prepare_cia_by_x
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jsr tape_motor_on
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// Clear color data ($0800)
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ldy #$00
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!:
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lda #(CONFIG_COLOR_TXT * $10 + CONFIG_COLOR_BG)
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sta $0800, y
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sta $0900, y
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sta $0A00, y
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sta $0B00, y
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iny
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bne !-
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// Make sure the row where the chart is being created is not visible
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lda #(CONFIG_COLOR_BG * $10 + CONFIG_COLOR_BG)
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ldy #$28
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!:
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sta $0800 + __ha_start * 40 - 1, y
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dey
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bne !-
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// Clear bitmap data ($2000)
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lda #$20
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sta SAL+1
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tya // put 0 to .A
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sta SAL+0
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!:
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sta (SAL), y
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iny
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bne !-
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inc SAL+1
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ldx SAL+1
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cpx #$40
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bne !-
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// Set graphics mode
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lda #$28 // graphics start at $2000, color at $0800
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sta VIC_YMCSB
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lda #$3B // set bit 5 to enable graphic mode
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sta VIC_SCROLY
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// Prepare lookup tables - to speed drawing, we are going to use two of them:
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// - byte offset table will tell us which byte in memory to alter
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// - mask will allow us to quickly put the pixel
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ldx #$00 // loop index
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ldy #$00 // temporary value for mask calculation
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!:
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// Byte offset is simple, just zero the 3 least significant bits
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txa
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and #%11111000
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sta __ha_offsets, x
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// Mask changes with each iteration, use our temporary value in .Y
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tya
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clc
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ror
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bne !+
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lda #%10000000
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!:
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tay
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sta __ha_masks, x
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// Next iteration
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inx
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bne !--
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// Generate helpercode for screen scrolling
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jsr tape_head_align_gen_code
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tape_head_align_loop_1:
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// XXX check for STOP key, possibly terminate
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// Scroll the whole chart one line down
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ldx #$00
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!:
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jsr __ha_scroll // scroll one column down, using fast generated code
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txa
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clc
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adc #$08
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tax
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bne !-
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// XXX draw helper lines
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// Initialize counter
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lda #$80
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sta __ha_counter + 1
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lda #$00
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sta __ha_counter + 0
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sta __ha_counter + 2
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// Skip 2 pulses, these measurements will be too imprecise
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jsr tape_head_align_get_pulse
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jsr tape_head_align_get_pulse
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tape_head_align_loop_2:
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// Retrieve actual pulse length
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jsr tape_head_align_get_pulse
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cmp #$FF
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beq tape_head_align_drawn // skip drawing for too long pulses
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// Put pulse on the screen; center the chart horizontaly, with some margin from top
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.label __ha_chart = $2000 + 8 * (40 * __ha_start + 4)
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tax
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lda __ha_offsets, x
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tay
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lda __ha_masks, x
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ora __ha_chart + 7, y
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sta __ha_chart + 7, y
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// FALLTROUGH
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tape_head_align_drawn:
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lda __ha_counter + 2
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beq tape_head_align_loop_2
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bne tape_head_align_loop_1
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tape_head_align_quit:
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// Clear screen, restore old display settings
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jsr cint_legacy
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// XXX restore COLOR, VIC_EXTCOL, VIC_BGCOL0, CIA2_PRA
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cli
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rts // XXX perform new after quit
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#endif // ROM layout
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#endif // CONFIG_TAPE_HEAD_ALIGN
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