18 lines
443 B
Plaintext
18 lines
443 B
Plaintext
LoopsWhile: PHA ;push accumulator onto stack
|
|
|
|
LDA #$00 ;the 6502 is an 8-bit processor
|
|
STA Ilow ;and so 1024 ($0400) must be stored in two memory locations
|
|
LDA #$04
|
|
STA Ihigh
|
|
WhileLoop: LDA Ilow
|
|
BNE NotZero
|
|
LDA Ihigh
|
|
BEQ EndLoop
|
|
NotZero: JSR PrintI ;routine not implemented
|
|
LSR Ihigh ;shift right
|
|
ROR Ilow ;rotate right
|
|
JMP WhileLoop
|
|
|
|
EndLoop: PLA ;restore accumulator from stack
|
|
RTS ;return from subroutine
|