Power ISA™ Version 2.03 - Power.org

Version 2.03
5.10.4 Vector Floating-Point Compare Instructions
The Vector Floating-Point Compare instructions compare
two Vector Registers word element by word element,
interpreting the elements as single-precision
floating-point numbers. With the exception of the Vector
Compare Bounds Floating-Point instruction, they set
the target Vector Register, and CR Field 6 if Rc=1, in
the same manner as do the Vector Integer Compare
instructions; see Section 5.9.2.
The Vector Compare Bounds Floating-Point instruction
sets the target Vector Register, and CR Field 6 if Rc=1,
to indicate whether the elements in VRA are within the
bounds specified by the corresponding element in
VRB, as explained in the instruction description. A single-precision
floating-point value x is said to be “within
the bounds” specified by a single-precision floating-point
value y if -y ≤ x ≤ y.
Vector Compare Bounds Single-Precision
VC-form
vcmpbfp VRT,VRA,VRB ( Rc=0 )
vcmpbfp. VRT,VRA,VRB ( Rc=1 )
4 VRT VRA VRB Rc 966
0 6 11 16 21 22 31
do i=0 to 127 by 32
le ( (VRA) i:i+31 ≤ fp (VRB) i:i+31 )
ge ( (VRA) i:i+31 ≥ fp -(VRB) i:i+31 )
VRT i:i+31 ¬le || ¬ge || 30 0
if Rc=1 then do
ib (VRT= 128 0)
CR6 0b00 || ib || 0b0
For each vector element i from 0 to 3, do the following.
Single-precision floating-point word element i in
VRA is compared to single-precision floating-point
word element i in VRB. A 2-bit value is formed that
indicates whether the element in VRA is within the
bounds specified by the element in VRB, as follows.
- Bit 0 of the 2-bit value is set to 0 if the element
in VRA is less than or equal to the element in
VRB, and is set to 1 otherwise.
- Bit 1 of the 2-bit value is set to 0 if the element
in VRA is greater than or equal to the negation
of the element in VRB, and is set to 1 otherwise.
The 2-bit value is placed into the high-order two
bits of word element i of VRT and the remaining
bits of element i are set to 0.
If Rc=1, CR field 6 is set as follows.
Bit Description
0 Set to 0
1 Set to 0
2 Set to indicate whether all four elements in VRA
are within the bounds specified by the corresponding
element in VRB, otherwise set to 0.
3 Set to 0
Special Registers Altered:
CR6
(if Rc=1)
Programming Note
Each single-precision floating-point word element
in VRB should be non-negative; if it is negative, the
corresponding element in VRA will necessarily be
out of bounds.
One exception to this is when the value of an element
in VRB is -0.0 and the value of the corresponding
element in VRA is either +0.0 or -0.0.
+0.0 and -0.0 compare equal to -0.0.
Vector Compare Equal To
Single-Precision
VC-form
vcmpeqfp VRT,VRA,VRB ( Rc=0 )
vcmpeqfp. VRT,VRA,VRB ( Rc=1 )
4 VRT VRA VRB Rc 198
0 6 11 16 21 22 31
do i=0 to 127 by 32
VRT i:i+31 ((VRA) i:i+31 = fp (VRB) i:i+31 ) ? 32 1 : 32 0
if Rc=1 then do
t ( VRT= 128 1 )
f ( VRT= 128 0 )
CR6 t || 0b0 || f || 0b0
For each vector element i from 0 to 3, do the following.
Single-precision floating-point element i in VRA is
compared to single-precision floating-point element
i in VRB. Word element i in VRT is set to all
1s if single-precision floating-point element i in
VRA is equal to single-precision floating-point element
i in VRB, and is set to all 0s otherwise.
If the source element i in VRA or the source element
i in VRB is a NaN, VRT is set to all 0s, indicating
“not equal to”. If the source element i in VRA
and the source element i in VRB are both infinity
with the same sign, VRT is set to all 1s, indicating
“equal to”.
Special Registers Altered:
CR6
(if Rc=1)
Chapter 5. Vector Processor [Category: Vector]
189