Texas Instruments TMS320C28x - Page 505

SUBCUL ACC,loc32
6-348
Example 1
; Calculate unsigned: Quot32 = Num32/Den32, Rem32 = Num32%Den32
MOVB ACC,#0 ; Zero ACC
MOVL P,@Num32 ; Load P register with Num32
RPT #31 ; Repeat operation 32 times
||SUBCUL ACC,@Den32 ; Conditional subtract with Den32
MOVL @Rem32,ACC ; Store remainder in Rem32
MOVL @Quot32,P ; Store quotient in Quot32
Example 2
; Calculate signed: Quot32 = Num32/Den32, Rem32 = Num32%Den32
CLRC TC ; Clear TC flag, used as sign flag
MOVL ACC,@Den32 ; Load ACC with contents of Den32
ABSTC ACC ; Take absolute value, TC = sign ^ TC
MOVL XT,@ACC ; Temp save denominator in XT register
MOVL ACC,@Num32 ; Load ACC register with Num32
ABSTC ACC ; Take abs value, TC = sign ^ TC
MOVL P,@ACC ; Load P register with numerator
MOVB ACC,#0 ; Zero ACC
RPT #31 ; Repeat operation 32 times
||SUBCUL ACC,@XT ; Conditional subtract with denominator
MOVL @Rem32,ACC ; Store remainder in Rem32
MOVL ACC,@P ; Load ACC with quotient
NEGTC ACC ; Negate ACC if TC=1 (negative result)
MOVL @Quot32,ACC ; Store quotient in Quot32
Example 3
; Calculate unsigned: Quot64 = Num64Den32, Rem32 = Num64%Den32
MOVB ACC,#0 ; Zero ACC
MOVL P,@Num64+2 ; Load P with high 32-bits of Num64
RPT #31 ; Repeat operation 32 times
||SUBCUL ACC,@Den32 ; Conditional subtract with Den32
MOVL @Quot64+2,P ; Store high 32 bit quotient in Quot64
MOVL P,@Num64+0 ; Load P with low 32-bits of Num64
RPT #31 ; Repeat operation 32 times
||SUBCUL ACC,@Den32 ; Conditional subtract with Den32
MOVL @Rem32,ACC ; Store remainder in Rem32
MOVL @Quot64+0,P ; Store low 32 bit quotient in Quot64