VFPSupport_ElementaryFunctions (changes)
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VFPSupport
» SWI Calls
» VFPSupport_ElementaryFunctions
VFPSupport_ElementaryFunctions
(SWI &58ECA)
| Entry | |
|---|---|
| R0 | Flags (reserved for future use, set to 0) |
| Exit | |
|---|---|
| R0 | Number of functions provided by this version of VFPSupport |
| R1 | Pointer to branch table for single precision functions |
| R2 | Pointer to branch table for double precision functions |
| All other registers preserved | |
Use
This call returns tables of VFP implementations of the elementary functions, jumping to the Nth table entry will run on one of the following functions which are given their C standard function names for convenience here, but other languages may give them different names:
| Table entry | C name | Equivalent FPA op | Equivalent VFP op |
|---|---|---|---|
| 0 | sin(x) | SIN | – |
| 1 | cos(x) | COS | – |
| 2 | tan(x) | TAN | – |
| 3 | asin(x) | ASN | – |
| 4 | acos(x) | ACS | – |
| 5 | atan(x) | ATN | – |
| 6 | atan2(y,x) | POL | – |
| 7 | log(x) | LGN | – |
| 8 | log10(x) | LOG | – |
| 9 | exp(x) | EXP | – |
| 10 | pow(x,y) | POW | – |
| 11 | fma(x,y,z) | – | VFMA |
Notes
When calling the above functions, the following rules apply:
- The functions will preserve 8 byte stack alignment
- D0-D7 (or S0-S15 for single precision),
andplus the usualAPCS registers (a1-a4, ip, lr) may be corrupted during the call - Flush to zero mode must be off
In the event of an exception during calculations, the corresponding FPSCR cumulative flags bits will be updated and optionally a floating point error thrown if enabled in the exception trap bits.
See also
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