Infineon Technologies C166S V2 User Manual page 341

CoMACMR
Group
Syntax
Source Operand(s)
Destination Operand(s)
Operation
IF (MP = 1) THEN
ELSE
END IF
(MAL) ← 0
((IDXi(-*))) ← ((IDXi))
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;
and next, 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 MSL
* *
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.
User Manual
Multiply-Accumulate & Move & Round
Multiply/Multiply-Accumulate Instructions
CoMACMR op1, op2, rnd
op1, op2 → WORD
ACC → 40-bit signed value
(tmp) ← (((op1)) * ((op2))) <<1
(ACC) ← (tmp) - (ACC) + 00 0000 8000h
(tmp) ← ((op1))*((op2))
(ACC) ← (tmp) - (ACC) + 00 0000 8000h
ME MSV
* *
Detailed Instruction Description
MC MZ
* *
8-341
User Manual
C166S V2
CoMACMR
MN Sat.
* yes
V 1.7, 2001-01