; ******************************************* ; * PAT80 COMPOSITE PAL VIDEO ADAPTER * ; * Video generator module * ; ******************************************* ; Implemented following timings in http://blog.retroleum.co.uk/electronics-articles/pal-tv-timing-and-voltages/ ; Every line, for 46 times, it loads a byte from memory into PORTA register and then shifts the byte to the left to show another bit (do it 7 times) ; This also displays byte's MSB pixel "for free", as the video pin is PD7 (last bit of PORTA). ; This module generates a Composite PAL monochrome signal with a resolution ; of 416x304 pixels of which only 368x256 pizels are visible (= 46x29 characters). ; The signal is generated using 16-bit Timer1 and interrupts. ; How does it work: ; The screen draw is divided in phases. Every phase does something. I.e. phases 0 to 9 ; represents the first 5 long syncs: ; (sync goes low, wait 30uS, sync goes high, wait 2uS) x 5 times = 10 phases ; When the interrupt is called, it uses register r25 (STATUS) to decide what to do. ; ; STATUS TABLE: ; R25 (STATUS): Current status (what the interrupt should do when fired): ; 0-9 = long sync ; 10-19 = short sync ; 20-44 = draw empty lines (top vertical padding) ; 45 = draw lines (draw 304 lines complete with line sync and back porch, then start short ; sync: sync pin low and next interrupt after 2uS) ; 46-70 = draw empty lines (bottom vertical padding) ; 71-82 = short sync ; 83-255 = invalid state or screen draw finished: set to 0 and restart from first long sync start .equ TIMER_DELAY_60US = 65535 - 1409 ; 719 cycles @ 24Mhz (minus overhead) .equ TIMER_DELAY_30US = 65535 - 690 ; 719 cycles @ 24Mhz (minus overhead) .equ TIMER_DELAY_2US = 65535 - 17 ; 48 cycles @ 24Mhz (minus overhead) .equ TIMER_DELAY_4US = 65535 - 64 ; 96 cycles @ 24Mhz (minus overhead) .equ BACK_PORCH_DELAY = 234 ; 186 cycles back porch + 48 cycles to leave 2 chunks empty (image padding) ; ********* FUNCTIONS CALLED BY INTERRUPT *********** on_tim1_ovf: ; TODO: save BUSY pin status and restore it before RETI, because it could be in BUSY status when interrupted ; set BUSY pin to indicate the mc is unresponsive from now on sbi PORTD, BUSY_PIN ; called by timer 1 two times per line (every 32 uS) during hsync, unless drawing picture. inc STATUS ; if STATUS >= 152 then STATUS=0 cpi STATUS, 152 ; TODO: Added a seventh sync pulse at end of screen because at the first short sync after the image, the timer doesn't tick at the right time brlo switch_status clr STATUS ; check status and decide what to do switch_status: cpi STATUS, 10 brlo long_sync ; 0-9: long sync cpi STATUS, 20 brlo short_sync ; 10-19: short sync cpi STATUS, 92 brlo empty_line ; 20-91: empty lines breq start_draw_picture ; 92: draw picture cpi STATUS, 140 brlo empty_line ; 93-139 = draw empty lines jmp short_sync ; 140-151 = short sync ; reti is at end of all previous jumps start_draw_picture: jmp draw_picture ; the breq instruction can branch only relatively -63 to +64 long_sync: ; long sync: 30uS low (719 cycles @ 24Mhz), 2uS high (48 cycles @ 24Mhz) sbis PORTC, SYNC_PIN ; if sync is high (sync is not occuring) skip next line jmp long_sync_end ; sync pin is high (sync is not occuring) cbi PORTC, SYNC_PIN ; sync goes low (0v) ; 2 cycle ; set timer in 30uS (reset timer counter) ldi r27, high(TIMER_DELAY_30US) ldi r26, low(TIMER_DELAY_30US) sts TCNT1H,r27 sts TCNT1L,r26 ; clear BUSY pin to indicate the mc is again responsive from now on cbi PORTD, BUSY_PIN reti long_sync_end: ; sync pin is low (sync is occuring) sbi PORTC, SYNC_PIN ; sync goes high (0.3v) ; set timer in 2uS: ldi r27, high(TIMER_DELAY_2US) ldi r26, low(TIMER_DELAY_2US) sts TCNT1H,r27 sts TCNT1L,r26 ; clear BUSY pin to indicate the mc is again responsive from now on cbi PORTD, BUSY_PIN reti short_sync: ; short sync: 2uS low (48 cycles @ 24Mhz), 30uS high (720 cycles @ 24Mhz) sbis PORTC, SYNC_PIN ; if sync is high (sync is not occuring) skip next line jmp short_sync_end ; sync pin is high (sync is not occuring) cbi PORTC, SYNC_PIN ; sync goes low (0v) ; 2 cycle ; set timer in 2uS (reset timer counter) ldi r27, high(TIMER_DELAY_2US) ldi r26, low(TIMER_DELAY_2US) sts TCNT1H,r27 sts TCNT1L,r26 ; clear BUSY pin to indicate the mc is again responsive from now on cbi PORTD, BUSY_PIN reti short_sync_end: ; sync pin is low (sync is occuring) sbi PORTC, SYNC_PIN ; sync goes high (0.3v) ; set timer in 30uS: ldi r27, high(TIMER_DELAY_30US) ldi r26, low(TIMER_DELAY_30US) sts TCNT1H,r27 sts TCNT1L,r26 ; clear BUSY pin to indicate the mc is again responsive from now on cbi PORTD, BUSY_PIN reti empty_line: ; line sync: 4uS low (96 cycles @ 24Mhz), 60uS high (1440 cycles @ 24Mhz) sbis PORTC, SYNC_PIN ; if sync is high (sync is not occuring) skip next line jmp empty_line_end ; sync pin is high (sync is not occuring) cbi PORTC, SYNC_PIN ; sync goes low (0v) ; 2 cycle ; set timer in 2uS (reset timer counter) ldi r27, high(TIMER_DELAY_4US) ldi r26, low(TIMER_DELAY_4US) sts TCNT1H,r27 sts TCNT1L,r26 ; clear BUSY pin to indicate the mc is again responsive from now on cbi PORTD, BUSY_PIN reti empty_line_end: ; sync pin is low (sync is occuring) sbi PORTC, SYNC_PIN ; sync goes high (0.3v) ; set timer in 30uS: ldi r27, high(TIMER_DELAY_60US) ldi r26, low(TIMER_DELAY_60US) sts TCNT1H,r27 sts TCNT1L,r26 ; clear BUSY pin to indicate the mc is again responsive from now on cbi PORTD, BUSY_PIN reti draw_picture: ; save X register push XH push XL ; set X register to framebuffer start ldi XH, high(FRAMEBUFFER) ldi XL, low(FRAMEBUFFER) ; start 256 picture lines ldi LINE_COUNTER, SCREEN_HEIGHT-1 ; line counter h_picture_loop: ; **** start line sync: 4uS, 96 cycles @ 24Mhz ; video pin goes low before sync clr VG_HIGH_ACCUM ; 1 cycle out VIDEO_PORT_OUT, VG_HIGH_ACCUM ; 1 cycle cbi PORTC, SYNC_PIN ; sync goes low (0v) ; 2 cycle ldi VG_HIGH_ACCUM, 31 ; 1 cycle l_sync_pulse_loop: ; requires 3 cpu cycles dec VG_HIGH_ACCUM ; 1 cycle brne l_sync_pulse_loop ; 2 cycle if true, 1 if false sbi PORTC, SYNC_PIN ; sync goes high (0.3v) ; **** end line sync ; **** start line back porch: 8uS, 192 cycles @ 24Mhz ; leave time at the end for line setup and draw_line call ldi VG_HIGH_ACCUM, BACK_PORCH_DELAY/3 ; 1 cycle l_sync_back_porch_loop: dec VG_HIGH_ACCUM ; 1 cycle brne l_sync_back_porch_loop ; 2 cycle if true, 1 if false ; **** end back porch call draw_line ; 3 cycles (+ 3 to come back to on_line_drawn) dec LINE_COUNTER ; decrement line countr ; 1 cycle brne h_picture_loop ; if not 0, repeat h_picture_loop ; 2 cycle if true, 1 if false ; end picture lines ; restore X register pop XL pop XH ; video pin goes low before sync clr VG_HIGH_ACCUM ; 1 cycle out VIDEO_PORT_OUT, VG_HIGH_ACCUM ; 1 cycle ; immediately start first end-screen short sync: inc STATUS jmp short_sync ; reti is in short_sync ; end draw_picture draw_line: ; NO loops, as this is time-strict ; 46 chunks of 8 pixels ; chunk 1 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 2 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 3 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 4 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 5 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 6 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 7 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 8 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 9 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 10 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 11 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 12 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 13 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 14 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 15 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 16 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 17 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 18 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 19 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 20 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 21 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 22 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 23 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 24 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 25 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 26 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 27 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 28 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 29 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 30 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 31 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 32 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 33 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 34 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 35 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 36 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 37 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 38 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 39 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 40 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 41 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 42 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 43 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 44 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 45 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; chunk 46 ld A, X+ ; load pixel ; 2 cycles out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle nop ; 1 cycle lsr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ; blank right margin clr A ; 1 cycle out VIDEO_PORT_OUT, A ; 1 cycle ldi VG_HIGH_ACCUM, 28 ; 1 cycle eol_porch_loop: ; requires 3 cpu cycles dec VG_HIGH_ACCUM ; 1 cycle brne eol_porch_loop ; 2 if jumps, 1 if continues ret