RCPDP
Double-Precision Floating-Point Reciprocal Approximation
3-198
Instruction Set
SPRU733
Note:
1) If
src2
is SNaN, NaN_out is placed in
dst
and the INVAL and NAN2 bits
are set.
2) If
src2
is QNaN, NaN_out is placed in
dst
and the NAN2 bit is set.
3) If
src2
is a signed denormalized number, signed infinity is placed in
dst
and the DIV0, INFO, OVER, INEX, and DEN2 bits are set.
4) If
src2
is signed 0, signed infinity is placed in
dst
and the DIV0 and INFO
bits are set.
5) If
src2
is signed infinity, signed 0 is placed in
dst
.
6) If the result underflows, signed 0 is placed in
dst
and the INEX and
UNDER bits are set. Underflow occurs when 2
1022
src2
infinity.
Pipeline
Stage
E1
E2
Read
src2_l
src2_h
Written
dst_l
dst_h
Unit in use
.S
If
dst
is used as the source for the
ADDDP
,
CMPEQDP
,
CMPLTDP
,
CMPGTDP
,
MPYDP
, or
SUBDP
instruction, the number of delay slots can be
reduced by one, because these instructions read the lower word of the DP
source one cycle before the upper word of the DP source.
Instruction Type
2-cycle DP
Delay Slots
1
Functional Unit
Latency
1
See Also
RCPSP, RSQRDP
Example
RCPDP .S1
A1:A0,A3:A2
Before instruction
2 cycles after instruction
A1:A0 4010 0000h
0000 0000h
A1:A0 4010 0000h
0000 0000h
4.00
A3:A2 xxxx xxxxh
xxxx xxxxh
A3:A2 3FD0 0000h
0000 0000h
0.25
Pipeline