S3C84BB Datasheet, PDF (205/361 Pages) Samsung semiconductor – 8-BIT CMOS

S3C84BB/F84BB
INSTRUCTION SET
RL — Rotate Left
RL
dst
Operation:
C ← dst (7)
dst (0) ← dst (7)
dst (n + 1) ← dst (n), n = 0–6
The contents of the destination operand are rotated left one bit position. The initial value of bit 7 is
moved to the bit zero (LSB) position and also replaces the carry flag, as shown in the figure below.
7
0
C
Flags:
Format:
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.
opc
dst
Bytes
2
Cycles
4
4
Opcode
(Hex)
90
91
Addr Mode
dst
R
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 the 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 (C) and the overflow (V) flags.
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