Texas Instruments TMS320C67X/C67X+ DSP - Manual (Page 327)

Subtract Two Unsigned Integers Without Saturation SUBU
3-267 Instruction Set SPRU733
Example SUBU .L1 A1,A2,A5:A4
Before instruction 1 cycle after instruction
A1 0000 325Ah 12810 †
A1 0000 325Ah
A2 FFFF FF12h 4294967058 † A2 FFFF FF12h
A5:A4 xxxx xxxxh xxxx xxxxh A5:A4 0000 00FFh 0000 3348h −4294954168
‡
† Unsigned 32-bit integer
‡ Signed 40-bit (long) integer