Conditional Mr Saturation - Analog Devices adsp-2100 Manual

Note that this instruction is a special case of MR + xop * yop, with yop set
to zero.
Z: Destination register
Syntax:
IF MV SAT MR ;
Description:
Test the MV (MAC Overflow) bit in the Arithmetic Status
Register (ASTAT), and if set, then saturate the lower-order 32 bits of the
40-bit MR register; if the MV is not set then perform a no-operation.
Saturation of MR is executed with this instruction for one cycle only; MAC
saturation is not a continuous mode that is enabled or disabled. The
saturation instruction is intended to be used at the completion of a series
of multiply/accumulate operations so that temporary overflows do not
cause the accumulator to saturate.
The saturation result depends on the state of MV and on the sign of MR
(the MSB of MR2). The possible results after execution of the saturation
instruction are shown in the table below.
MV MSB of MR2
0 0
0 1
1 0
1 1
Status Generated:
Instruction Format:
Saturate MR operation, Instruction Type 25:
23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 0 0 0 0

CONDITIONAL MR SATURATION

MR contents after saturation
No change
No change
00000000 0111111111111111 1111111111111111
11111111 1000000000000000 0000000000000000
No status bits affected.
1 0 1 0 0 0
COND: condition
0 0 0 0 0 0 0 0 0 0 0 0 0
MAC
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