Computer Hardware User's Guide

Repeat Block RPTB
13-209 Assembly Language Instructions
Syntax RPTB src
Operation src → RE
1 → ST (RM)
Next PC → RS
Operands
src long-immediate addressing mode
Opcode
31 24 23 16 8 7 015
0110 0 0
01 src
Description RPTB allows a block of instructions to be repeated RC register + 1 times with-
out any penalty for looping. This instruction activates the block repeat mode
of updating the PC. The src operand is a 24-bit unsigned immediate value that
is loaded into the repeat end-address (RE) register. A 1 is written into the re-
peat mode bit of status register ST (RM) to indicate that the PC is being up-
dated in the repeat mode. The address of the next instruction is loaded into the
repeat start-address (RS) register.
RE should be greater than or equal to RS (RE RS). Otherwise, the code
does not repeat, even though the RM bit remains set to 1.
Cycles 4
Status Bits LUF Unaffected
LV Unaffected
UF Unaffected
N Unaffected
Z Unaffected
V Unaffected
C Unaffected
OVM Operation is not affected by OVM bit value.Mode Bit