110
edits
Changes
Add "Floating-Point Behavior" section
| c0-c95
| c0-c95
| Vector uniform registers.
| Vector uniform registers.
|}
== Floating-Point Behavior ==
The PICA200 is not IEEE-compliant. It has positive and negative infinities and NaN, but does not seem to have negative 0. Several instructions also have behavior that differs from the IEEE functions. Here are the results from some tests done on hardware:
{| class="wikitable" border="1"
|-
! Computation
! Result
! Notes
|-
| inf/NaN * 0
| 0
| Including inside MUL, MAD, DP4, etc.
|-
| +inf - +inf
| NaN
| Indicates +inf is real inf, not FLT_MAX
|-
| rsq(rcp(-inf))
| +inf
| Indicates that there isn't -0.0.
|- style="border-top: double"
| rcp(0)
| +inf
|
|-
| rcp(+inf)
| 0
|
|-
| rcp(NaN)
| NaN
|
|- style="border-top: double"
| rsq(-0)
| +inf
|
|-
| rsq(-2)
| NaN
|
|-
| rsq(+inf)
| 0
|
|-
| rsq(-inf)
| NaN
|
|-
| rsq(NaN)
| NaN
|
|- style="border-top: double"
| max(0, +inf)
| +inf
|
|-
| max(0, -inf)
| -inf
|
|-
| max(0, NaN)
| NaN
|
|-
| max(NaN, 0)
| 0
|
|-
| max(-inf, +inf)
| +inf
|
|- style="border-top: double"
| min(0, +inf)
| 0
|
|-
| min(0, -inf)
| -inf
|
|-
| min(0, NaN)
| NaN
|
|-
| min(NaN, 0)
| 0
|
|-
| min(-inf, +inf)
| -inf
|
|}
|}