Z : R - Lucent Technologies DSP1617 Information Manual

DSP1611/17/18/27/28/29 DIGITAL SIGNAL PROCESSOR
Instruction Set Summary

Z : R

(exchange register with Y-space memory)
temp ← (R); then
(R) ← (*rM); then
modify rM (first action); then
(*rM) ← temp; then
modify rM (second action)
The contents of the Y-space memory location(s) pointed to by rM are exchanged with the current contents of regis-
ter R, which are sign- or zero-extended to 16 bits if necessary. The pointer rM is modified after each of the two
memory accesses according to bits zero and one of the Z field. rM is specified by bits two and three of the Z field:
00 - r0
The available options for the postmodification are specified by the two least significant bits of the Z field as follows:
Symbol 2 LSBs of Z
*rMzp 00
*rMpz 01
*rMm2 10
†
*rMjk 11
† Code 11, in this case, means add the current value of the j register to rM after reading *rM, and then add the
current value of the k register to rM after writing *rM.
Register R is one of the general sets of registers listed under the long immediate load instruction. Register sources
c0, c1, and c2 are less than 16 bits and are sign-extended. Register source auc is less than 16 bits and is zero-
extended.
Note: Writing the psw also writes the a0 and a1 guard bits.
Bit 15 14
Field 0 1
Note: R and rM must not be the same register (e.g., r2pz : r2). The eight logical PIO registers pdx0 through pdx7
cannot be used in compound data moves.
B-15
01 - r1
First Action
no action (zero)
postincrement (plus)
postdecrement (minus)
postincrement by (j)
13 12 11 10
1 0 1 X
Words: 1
Cycles: 2
Group: Data Move
Addressing: Register, Register Indirect
Flags affected: None
Interruptible: Yes
Cacheable: Yes
Format: 7
DRAFT COPY
10 - r2
Second Action
postincrement (plus)
no action (zero)
postincrement by two (+2)
postincrement by (k)
9—4
R
Information Manual
April 1998
11 - r3
3—0
Z
Lucent Technologies Inc.