Infineon Technologies C166S V2, User Manual

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User Manual
C166S V2
Detailed Instruction Description
User Manual 8-331 V 1.7, 2001-01
CoMAC
Multiply-Accumulate
CoMAC
Group Multiply/Multiply-Accumulate Instructions
Syntax CoMAC op1, op2
Source Operand(s) op1, op2
→
WORD
Destination Operand(s) ACC
→
40-bit signed value
Operation
IF (MP = 1) THEN
(tmp)
←
((op1) * (op2)) <<1
(ACC)
←
(ACC) + (tmp)
ELSE
(tmp)
←
(op1) * (op2)
(ACC)
←
(ACC) + (tmp)
END IF
Description
Multiplies the two signed 16-bit source operands op1 and op2. The resulting signed
32-bit product is first sign-extended; then, if the MP flag is set, it is one-bit left shifted;
then, it is added to the 40-bit ACC register contents before being stored in the 40-bit
ACC register.
MAC Flags
MV Set if an arithmetic overflow occurred, i.e. the result cannot be
represented in the 40-bit data type. Cleared otherwise.
MSL Set if the contents of ACC is automatically saturated. Not affected
otherwise.
ME Set if the MAE is used. Cleared otherwise.
MSV Set if an arithmetic overflow occurred. Not affected otherwise.
MC Set if a carry is generated. Cleared otherwise.
MZ Set if result equals zero. Cleared otherwise.
MN Set if the most significant bit of the result is set. Cleared otherwise.
MV MSL ME MSV MC MZ MN Sat.
* * * * * * * yes