Texas Instruments TMS320C67X/C67X+ DSP manual Absolute Value With Saturation

ABS Absolute Value With Saturation

				Absolute Value With Saturation
ABS
Syntax					ABS (.unit) src2, dst
					.unit = .L1 or .L2
Compatibility					C62x, C64x, C67x, and C67x+ CPU
Opcode
31	29	28	27	23		22	18	17	13	12	11	5	4	3	2	1	0

creg

z

dst

src2

0 0 0 0 0 x

op

1 1 0 s p

3	1	5	5	1	7	1	1
			Opcode map field used...	For operand type...	Unit	Opfield
			src2	xsint	.L1, .L2	001 1010
			dst	sint
			src2	slong	.L1, L2	011 1000
			dst	slong

Description

Execution

Pipeline

The absolute value of src2 is placed in dst.

if (cond)	abs(src2) → dst
else nop

The absolute value of src2 when src2 is an sint is determined as follows:

1)If src2 w 0, then src2 → dst

2)If src2 t 0 and src2 ￿ −231, then −src2 → dst

3)If src2 = −231, then 231 − 1 → dst

The absolute value of src2 when src2 is an slong is determined as follows:

1)If src2 w 0, then src2 → dst

2)If src2 t 0 and src2 ￿ −239, then −src2 → dst

3)If src2 = −239, then 239 − 1 → dst

Pipeline

StageE1

Read src2

Written dst

Unit in use .L

3-38 Instruction Set SPRU733