Computer Hardware User's Guide
Parallel ASH3 and STI
ASH3||STI
13-77
Assembly Language Instructions
Arithmetic right shift:
sign of
src2
→
src2
→ C
If the
count
operand is 0, no shift is performed, and the C bit is set to 0. The
count
and
dst
operands are assumed to be signed integers.
All registers are read at the beginning and loaded at the end of the execute
cycle. If one of the parallel operations (STI) reads from a register and the oper-
ation being performed in parallel (ASH3) writes to the same register, STI ac-
cepts the contents of the register as input before it is modified by the ASH3.
If
src2
and
dst2
point to the same location,
src2
is read before the write to
dst2.
Cycles 1
Status Bits These condition flags are modified only if the destination register is R7–R0.
LUF Unaffected
LV 1 if an integer overflow occurs; unchanged otherwise
UF 0
N MSB of the output
Z 1 if a 0 result is generated; 0 otherwise
V 1 if an integer overflow occurs; 0 otherwise
C Set to the value of the last bit shifted out; 0 for a shift count of 0
OVM Operation is not affected by OVM bit value.Mode Bit