Created
September 10, 2017 20:09
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VIC pseudocode (not necessarily accurate/rigorous, but useful enough to explain stuff)
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// Sometime outside of display area.. | |
VCBASE := 0 | |
VIDEO_COLOR_BUFFER := 0 | |
for RASTER in 0..312 { | |
for line_cycle in 0..63 { | |
badline_condition := (RASTER & 0x07) == (YSCROLL & 0x07) | |
if (badline_condition) { | |
MODE = MODE_DISPLAY | |
} | |
BA := line_cycle >= 12 && line_cycle <= 54 && badline_condition | |
if (line_cycle == 14) { | |
VC := VCBASE | |
VMLI := 0 | |
if (badline_condition) { | |
RC := 0 | |
} | |
} | |
if (line_cycle >= 15 && line_cycle <= 54) { | |
// c-access | |
if (badline_condition) { | |
VIDEO_COLOR_BUFFER[VMLI] := (COLOR_MEM[VC] << 8) | SCREEN_MEM[VC] | |
} | |
// g-access | |
DISPLAY := VIDEO_COLOR_BUFFER[VMLI] | |
VC := VC + 1 | |
VMLI := VMLI + 1 | |
} | |
if (line_cycle == 58 && RC == 7) { | |
MODE := MODE_IDLE | |
VCBASE := VC | |
badline_condition := (RASTER & 0x07) == (YSCROLL & 0x07) | |
if (badline_condition) { | |
MODE = MODE_DISPLAY | |
} | |
if (MODE == MODE_DISPLAY) { | |
RC := RC + 1 | |
} | |
} | |
badline_condition := (RASTER & 0x07) == (YSCROLL & 0x07) | |
if (badline_condition) { | |
MODE = MODE_DISPLAY | |
} | |
} | |
} |
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