Texas Instruments TMS320C67X/C67X+ DSP manual RCPSP, Rsqrdp, Unit in use

RCPDP Double-Precision Floating-Point Reciprocal Approximation

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 21022 t src2 t infinity.

Pipeline
	Pipeline	E1	E2
	Stage
	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		1
Latency
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

3-198 Instruction Set SPRU733