50
Vector Unit Instructions
If an illegal alignment (or element value) is attempted, something
will
be
loaded or stored, but probably not what was intended.
Normal
Normal loads and stores move a single memory item to or from an element
of a VU register. Items are
byte
(8 bit),
short
(16 bit),
long
(32 bit),
double
(64
bit), and
quad
or
rest
(128 bit). The memory address is byte aligned. The VU
element is aligned to the size of the item.
Quad and rest operands update the portion of the memory item or VU
register which fall within the aligned quad word.
Quad operations move a byte-aligned quad word up to the 16 byte
boundary, that is,
(address)
to
((address & ~15) + 15)
to/from VU register
element 0 to
(address & 15).
Rest is used to move a byte-aligned quad word up to the byte address, that
is,
(address & ~15)
to
(address - 1)
to/from VU register element
(16 - (address & 15))
to 15. A rest with a byte address of zero writes no
bytes.
The quad and rest pair can then move a byte-aligned quad word to/from an
entire vector register in two instructions. (This can also be performed with
two byte-aligned double instructions, although quad and rest allow the two
quad words to be disjoint.) A quad word on a quad word boundary can be
moved in one quad instruction.
lfv, sfv
4 8b every 4th,
unssigned (fourth pack)
quad+0 to 3
0, 8
<< 4
ltv, stv,
swv
8 16b (transpose, wrap)
quad
0-14 by 2
<< 4
Opcode
Memory Item
Memory
Alignment
VU Element
(legal values)
Offset Shift
Amount
T
rans
pos
e
Summary of Contents for Ultra64
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Page 10: ...10 ...
Page 12: ...12 Figure 6 2 buildtask Operation 137 ...
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Page 80: ...80 Vector Unit Instructions vmadm dres_int dres_int vconst 3 vmadn dres_frac vconst vconst 0 ...
Page 104: ...104 RSP Coprocessor 0 ...
Page 150: ...150 Advanced Information ...
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