S3F84B8_UM_REV 1.00 6 INSTRUCTION SET
6-70
6.3.57 RL — ROTATE LEFT
RL dst
Operation: C dst (7)
dst (0) dst (7)
dst (n + 1) dst (n), n = 0–6
The contents of destination operand are rotated left one bit position. The initial value of bit 7 is
moved to bit zero (LSB) position. It also replaces the carry flag.
70
C
Flags: C: Set if the bit rotated from the most significant bit position (bit 7) was “1”.
Z: Set if the result is “0”; cleared otherwise.
S: Set if the result bit 7 is set; cleared otherwise.
V: Set if arithmetic overflow occurred; cleared otherwise.
D: Unaffected.
H: Unaffected.
Format:
Bytes Cycles Opcode
(Hex)
Addr Mode
dst
opc dst 2 4 90 R
4 91 IR
Examples: Given register 00H = 0AAH, register 01H = 02H, and register 02H = 17H:
RL 00H Register 00H = 55H, C = “1”
RL @01H Register 01H = 02H, register 02H = 2EH, C = “0”
In the first example, if general register 00H contains the value 0AAH (10101010B), the statement
“RL 00H” rotates the 0AAH value left one bit position, leaving the new value 55H (01010101B)
and setting the carry and overflow flags.
To Next Page
Loading...
