F1 Z : At[L - Lucent Technologies DSP1617 Information Manual

Information Manual
April 1998

F1 Z : aT[l]

(multiply/ALU operation with parallel compound accumulator move)
perform operation F1 and in parallel, perform the following compound accumulator move:
temp ← (aT) or (aTl); then
(aT) or (aTl) ← (*rM); then
modify rM (first action);
(*rM) ← temp;
modify rM (second action)
This instruction performs the following operations (effectively in parallel):
1. The operation F1 is performed. The possible operations for F1 are as follows:
F1 Operation
0000 aD = pp = x * y
0001 aD = aS + pp = x * y
0010 p = x * y
0011 aD = aS – pp = x * y
0100 aD = p
0101 aD = aS + p
The value of S is zero to select a0 or one to select a1. The value of D selects aD and aT as follows:
D (bit 10) aD
0 a0
1 a1
aD and aT are opposites, and flags are modified based on the value computed by the DAU.
Note: For all diadic operations involving the y register, y is sign-extended to 36 bits before performing the
operation (including logical operations). (See
available when shifting the output of the p register into aS in the above operations.)
2. Save either the y or yl register into an internal temporary location (temp). aT is defined as the opposite of aD
for this instruction. If aS in the F1 operation is the same as aT, the value used in the F1 operation will be the
old value due to pipelining. The X field selects aT or aTl:
X = 0 → aTl
3. Access the Y-space location pointed to by rM, and write this value to the aT (or aTl) register. rM is specified
by the two most significant bits of the Z field:
00 - r0
4. Postmodify the value of rM using the first action described by the two least significant bits of the Z field
described below.
Lucent Technologies Inc.
DSP1611/17/18/27/28/29 DIGITAL SIGNAL PROCESSOR
F1 Operation
0110 nop
0111 aD = aS – p
1000 aD = aS | y
1001 aD = aS ^ y
1010 aS & y
aT
a1
a0
Section 3.3, Arithmetic and
X = 1 → aT
01 - r1
DRAFT COPY
Instruction Set Summary
F1
1011
1100
1101
1110
1111
Precision, for the options
10 - r2
Operation
aS – y
aD = y
aD = aS + y
aD = aS & y
aD = aS – y
11 - r3
B-38