Motorola DSP96002 - Manual (Page 856)

4 MOTOROLA
Operation:
S1.L * S2.L
→
D1.M:D1.L
(parallel data bus move)
D2.L - S3.L
→
D2.L
MPYS//SUB Integer Signed MPYS//SUB
Multiply and Subtract
Description:
Multiply the two signed operands S1 and S2 and store the product in the specified destination register D1.
The two source operands S1and S2 are 32-bit integers and are taken from the low portion of S1 and S2.
The result is a 64-bit signed integer stored in the middle and low portions of D1.
Simultaneously, subtract the low portion of the specified source operand S3 from the low portion of the des-
tination operand D2 and store the result in the low portion of the destination operand D2.
This instruction is enabled only in Integer Mode.
Input Operand(s) Precision: 32-bit integer.
Subtraction Output Operand Precision: 32-bit integer.
Multiplication Output Operand Precision: 64-bit integer.
CCR Condition Codes:
C - Set if borrow is generated from the MSB of the subtraction result. Cleared
otherwise.
V - Set if the subtraction result overflows. Cleared otherwise.
Z - Set if result of the subtraction is zero. Cleared otherwise.
N - Set if result of the subtraction is negative. Cleared otherwise.
I - Not affected.
LR - Not affected.
R - Not affected.
A - Not affected.
ER Status Bits: Not affected
IER Flags: Not affected
Assembler Syntax:
MPYS S1,S2,D1 SUB S3,D2
(move syntax - see the MOVE instruction de-
scription.)
MPYS S2,S1,D1 SUB S3,D2
(move syntax - see the MOVE instruction de-
scription.)