RLD
Rotate and Shift Group
Expansion:
Rotate Left Digit
Usage:
dec {r}
To do
Example
; Example
ld b, 5 ; move the value 5 to reg A
loop:
sla a ; shifts the value in A 1 bit to the left filling in the; lowest bit with 0
dec v ; decrement b (b--)
jp nz, loop ; jump condition if A (n)on-(z)ero then jump to loop label
ret ; return
ret
;dd
Second
ENTRY_POINT equ $8000 ; start of the empty memory
org ENTRY_POINT ; start
; ... code here
ret ; return to the system
end ENTRY_POINT ; end of file marker
Additional description area
- Point 1
- If decrementing allows the BC to go to 0 or if A equals the value at the memory location pointed to by HL (A = (HL)), the instruction is terminated2. If BC is not 0 and A ≠ (HL), the program counter is decremented by two and the instruction is repeated2.
- Point 3