Infineon Technologies C166S V2, User Manual

Page: 348 / 439

User Manual
C166S V2
Detailed Instruction Description
User Manual 8-348 V 1.7, 2001-01
CoMACMRu
Multiply-Accumulate & Move & Round
CoMACMRu
Group Multiply/Multiply-Accumulate Instructions
Syntax CoMACMRu op1, op2, rnd
Source Operand(s) op1, op2
→
WORD
Destination Operand(s) ACC
→
40-bit signed value
Operation
(tmp)
←
((op1))*((op2))
(ACC)
←
(tmp) - (ACC) + 00 0000 8000h
(MAL)
←
0
((IDXi(-*)))
←
((IDXi))
Description
Multiplies the two unsigned 16-bit source operands op1 and op2. The resulting
unsigned 32-bit product is first zero-extended; then, the 40-bit ACC register contents
are subtracted from the result. Finally, the result is 2s complement rounded before
being stored in the 40-bit ACC register. The MAL register is cleared. In parallel to the
arithmetic operation and to the two parallel reads, the data pointed to by IDXi overwrites
another data located in memory (DPRAM). The address of the overwritten data
depends on the operation executed on IDXi.
MAC Flags
MV Set if an arithmetic underflow 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 underflow occurred. Not affected otherwise.
MC Set if a borrow 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