2.2.38 (1) MULXS (B)
MULXS (MULtiply eXtend as Signed)
Multiply Signed
Operation
Rd
×
Rs
→
Rd
Assembly-Language Format
MULXS.B
Rs, Rd
Operand Size
Byte
Condition Code
H: Previous value remains unchanged.
N: Set to 1 if the result is negative; otherwise
cleared to 0.
Z: Set to 1 if the result is zero; otherwise
cleared to 0.
V: Previous value remains unchanged.
C: Previous value remains unchanged.
I
UI
H
U
N
Z
V
C
—
—
—
—
↕
↕
—
—
Description
This instruction multiplies the lower 8 bits of a 16-bit register Rd (destination operand) by the
contents of an 8-bit register Rs (source operand) as signed data and stores the result in the 16-bit
register Rd. If Rd is a general register, Rs can be the upper part (RdH) or lower part (RdL) of Rd.
The operation performed is 8-bit
×
8-bit
→
16-bit signed multiplication.
Available Registers
Rd: R0 to R7, E0 to E7
Rs: R0L to R7L, R0H to R7H
Operand Format and Number of States Required for Execution
Notes
Rd
Rs
Rd
Don’t care Multiplicand
×
Multiplier
→
Product
8 bits
8 bits
16 bits
Instruction Format
1st byte
2nd byte
3rd byte
4th byte
Register direct
MULXS.B
Rs, Rd
0
1
C
0
5
0
rs
rd
16
No. of
States
Addressing
Mode
Mnemonic
Operands
128