User`s guide

Inline Assembly Language and Intrinsics
Intrinsic Functions
158
Targeting MC56F83xx/DSP5685x Controllers
Multiplication/MAC
The intrinsic functions of the multiplication/MAC group are:
• mac_r
• msu_r
• mult
• mult_r
• L_mac
• L_msu
• L_mult
• L_mult_ls
mac_r
Multiply two 16-bit fractional values and add to 32-bit fractional value. Round into a
16-bit result, saturating if necessary. When an accumulator is the destination, zeroes
out the LSP portion.
Assumptions
OMR’s SA bit was set to 1 at least 3 cycles before this code, that is, saturation on data
ALU results enabled.
OMR’s R bit was set to 1 at least 3 cycles before this code, that is, 2’s complement
rounding, not convergent rounding.
Prototype
Word16 mac_r(Word32 laccum, Word16 sinp1, Word16 sinp2)