A 3200-color "slow but cool" display mode in the Apple IIGS paint program DreamGrafix that used 80% of CPU time for updating the palette registers as the display was being drawn and 20% for actual processing.
Coincidentally, SBC is also an instruction on the Apple IIGS's 65816 processor (and its predecessor, the 6502) that performs subtraction, normally
in binary. In 6502 processors with
decimal mode, SBC subtracts in binary
or packed binary-coded decimal depending on the decimal
flag. To subtract without borrow, insert a SEC
instruction before SBC, as SBC uses the carry bit as an
inverted borrow bit.
- Function: A + ~N + C => A
(that is, A + (-N-1) + C => A)
- Updates flags: S V . . . . Z C
- Opcode numbers:
Similar: ADC | CMP | CPX | CPY
See also: 6502 instructions | 6502 addressing modes