ceda2vga/src/vga.pio

.program vga_free_run

entrypoint_vga_free_run:
    pull
    mov y, osr

.wrap_target
    mov x, y
    wait irq 7
loop:
    out pins, 1 [2]
    jmp x-- loop
.wrap

.program vga_hsync

entrypoint_vga_hsync:
    pull
    mov isr, osr
    pull

.wrap_target
    set pins, 0 [1]
    irq set 0
    mov x, isr
hsync_pulse:
    jmp x-- hsync_pulse [3]

    set pins, 1 [1]
    set y, 27
hsync_back_porch:
    jmp y-- hsync_back_porch [16]
    irq set 7

    mov x, osr [3]
hsync_idle:
    jmp x-- hsync_idle [3]
.wrap


.program vga_vsync

entrypoint_vga_vsync:
    pull
    mov isr, osr
    pull

.wrap_target
    mov x, isr
vsync_pulse:
    wait irq 0
    set pins, 0
    jmp x-- vsync_pulse

    irq set 1

    mov x, osr
vsync_idle:
    wait irq 0
    set pins, 1
    jmp x-- vsync_idle

.wrap