Nintendo Ultra64 Programmer's Manual page 258

VMACF
31
COP2
0 1 0 0 1 0
6
Format:
vmacf vd, vs, vt
vmacf vd, vs, vt[e]
Description:
The 16-bit elements of vector register
elements of vector register
Bits 31...16 of the accumulator are clamped to 16 bit signed values and placed into vector register
vd
.
If an element specification
used as described below.
258
Vector Multiply-Accumulate
of Signed Fractions
26 25 24 21 20
1 e
1 4
vs
, and added to bits 47...16 of the accumulator.
e
is present for vector register
16 15 11 10
vt vs
5 5
vt are multiplied on an element-by-element basis to the
VMACF
6 5
vd VMACF
0 0 1 0 0 0
5 6
vt
, the selected scalar element(s) of
0
vt
is