INSTRUCTION DESCRIPTIONS
MOTOROLA INSTRUCTION SET DETAILS A - 91
At LA any two-word instruction*
Jcc REP
JCLR RESET
JSET RTI
JMP RTS
JScc STOP
JSR WAIT
*This restriction applies to the situation in which the
DSP56K simulator’s single-line assembler is used to
change the last instruction in a DO loop from a one-
word instruction to a two-word instruction.
Other Restrictions: DO SSH,xxxx
JSR to (LA) whenever the loop flag (LF) is set
JScc to (LA) whenever the loop flag (LF) is set
JSCLR to (LA) whenever the loop flag (LF) is set
JSSET to (LA) whenever the loop flag (LF) is set
A DO instruction cannot be repeated using the REP instruction.
Note: Due to instruction pipelining, if an AGU register (Mn, Nn, or Rn) is directly changed
with a MOVE-type instruction, the new contents may not be available for use until the
second following instruction. See the restrictions discussed in A.9.6 - R, N, and M Regis-
ter Restrictions on page A-310.This restriction also applies to the situation in which the
last instruction in a DO loop changes an address register and the first instruction at the
top of the DO loop uses that same address register. The top instruction becomes the fol-
lowing instruction because of the loop construct.
Similarly, since the DO instruction accesses the program controller registers, the DO
instruction must not be immediately preceded by any of the following instructions:
Immediately before DO MOVEC to LA, LC, SSH, SSL, or SP
MOVEM to LA, LC, SSH, SSL, or SP
MOVEP to LA, LC, SSH, SSL, or SP
MOVEC from SSH
MOVEM from SSH
MOVEP from SSH
DO Start Hardware Loop DO