Texas Instruments TMS320C67X/C67X+ DSP manual SUB2, Src1 and placed in the lower-half of dst

SUB2 Subtract Two 16-Bit Integers on Upper and Lower Register Halves

				Subtract Two 16-Bit Integers on Upper and Lower Register Halves
SUB2
Syntax					SUB2 (.unit) src1, src2, dst
					.unit = .S1 or .S2
Compatibility					C62x, C64x, C67x, and C67x+ CPU
Opcode
31	29	28	27	23		22	18	17	13	12	11	6	5	4	3	2	1	0

creg

3

z

1

dst		src2	src1		x	0 1 0 0 0	1	1	0	0	0	s	p
5	5		5	1								1	1
	Opcode map field used...			For operand type...						Unit
	src1			sint					.S1, .S2
	src2			xsint
	dst			sint

Description	The upper and lower halves of src2 are subtracted from the upper and lower
	halves of src1 and the result is placed in dst. Any borrow from the lower-half
	subtraction does not affect the upper-half subtraction. Specifically, the
	upper-half of src2 is subtracted from the upper-half of src1 and placed in the
	upper-half of dst. The lower-half of src2 is subtracted from the lower-half of
	src1 and placed in the lower-half of dst.

31	16	15	0
	a_hi		a_lo

src1

SUB2

	b_hi		b_lo
31	16	15	0
	a_hi − b_hi		a_lo − b_lo

src2

dst

3-268 Instruction Set SPRU733