Texas Instruments TMS320C28x Reference Manual page 491

SUB ACC,loc16 << #0...16
Repeat
Example
; Calculate signed value: ACC = (VarA << 10) − (VarB << 6);
SETC
MOV
SUB
6-334
If the operation is repeatable, then the instruction will be executed N+1
times. The state of the Z, N, C flags will reflect the final result. The V flag will
be set if an intermediate overflow occurs. The OVC flag will count
intermediate overflows, if overflow mode is disabled. If the operation is not
repeatable, the instruction will execute only once.
SXM
ACC,@VarA << #10
ACC,@VarB << #6
; Turn sign extension mode on
; Load ACC with VarA left shifted by 10
; Subtract VarB left shifted by 6 to ACC0