Vu Multiply Instructions; Figure 3-9 Vu Multiply Opcode Encoding; Table 3-4 Vu Multiply Instruction Summary - Nintendo Ultra64 Programmer's Manual

VU Multiply Instructions

Fmt S, T signed
0 0 0 sign, sign
0 0 1 sign, sign
0 1 0 NA, sign
0 1 1 sign, sign
1 0 0 uns, uns
1 0 1 sign, uns
Revision 1.0
VU Multiply Opcode Encoding
Figure 3-9
5 4
0 0
VU multiply instructions perform various multiplies, specified by the
following fields:
Element:
Vector or scalar element of
A: a
When
and load the accumulator. The round value is determined by the
format.
Format:
Select various product and result options.
product
The is the 32 bit signed result from the 16x16 signed multiply. Each
accumulator
element of the
result
The is the 16 bits of the accumulator written to
(32 bit) operands are supported by multiplying and accumulating the low 16
bits from one vector operand and the upper 16 bits from another vector
operand in several multiply instructions. Formats for various product and
result options are shown in Table 3-4.

Table 3-4 VU Multiply Instruction Summary

Prod
Round Value
Shift
<< 1 +32768
<< 1 +32768
NA +VT if Acc
<< 16 +31 if Prod
>> 16 0
0 0
3 2 0
format
a
== 1, Accumulate the product, otherwise round the product
is 48 bits wide (see "Accumulator" on page 36).
Result Clamping
b31-16 sign, b31-msb
b31-16 uns, b31-msb
b31-16 sign, b31-msb
b32-17 sign, b32-msb
b15-0 sign, b31-msb
b31-16 sign, b31-msb
VU Multiply Instructions
vt
.
vd
. Double precision
Instructions
vmulf, vmacf
vmulu, vmacu
vrndp, vrndn
vmulq, vmacq
vmudl, vmadl
vmudm, vmadm
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