ROL
Instruction: Rotate value left by specified number of bits.
ROL Value, < # > Bits
Result: Value is rotated left by Bits.
- Value (d-field) is the register to rotate left.
- Bits (s-field) is a register or a 5-bit literal whose value is the number of bits to rotate left.
Opcode Table:
–INSTR– ZCRI –CON– –DEST– –SRC– | Z Result | C Result | Result | Clocks |
001001 001i 1111 ddddddddd sssssssss | Result = 0 | D[31] | Written | 4 |
Concise Truth Table:
In | Out | ||||||
Destination | Source | Z | C | Effects | Destination | Z | C |
$0000_0000; 0 | $0000_0001; 1 | - | - | wz wc | $0000_0000; 0 | 1 | 0 |
$8765_4321; -2,023,406,815 | $0000_0004; 4 | - | - | wz wc | $7654_3218; 1,985,229,336 | 0 | 1 |
$7654_3218; 1,985,229,336 | $0000_000C; 12 | - | - | wz wc | $4321_8765; 1,126,270,821 | 0 | 0 |
$4321_8765; 1,126,270,821 | $0000_0010; 16 | - | - | wz wc | $8765_4321; -2,023,406,815 | 0 | 0 |
Explanation
ROL (Rotate Left) rotates Value left, Bits times. The MSBs rotated out of Value are rotated into its LSBs.
If the WZ effect is specified, the Z flag is set (1) if the resulting Value equals zero. If the WC effect is specified, at the end of the operation, the C flag is set equal to Value's original bit 31. The result is written to Value unless the NR effect is specified.
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