|
|||
| Products Download Events Support Videos | |||
Technical Support
On-Line Manuals
Assembler User Guide
Conventions and feedback
Overview of the Assembler
Overview of the ARM Architecture
Structure of Assembly Language Modules
Writing ARM Assembly Language
Condition Codes
Using the Assembler
Symbols, Literals, Expressions, and Operators
VFP Programming
Architecture support for VFP
Half-precision extension
Fused Multiply-Add extension
Extension register bank mapping
VFP views of the extension register bank
Load values to VFP registers
Conditional execution of VFP instructions
Floating-point exceptions
VFP data types
Extended notation
VFP system registers
FPSCR, the floating-point status and control regis
FPEXC, the floating-point exception register
FPSID, the floating-point system ID register
Flush-to-zero mode
When to use flush-to-zero mode
The effects of using flush-to-zero mode
Operations not affected by flush-to-zero mode
VFP vector mode
Vectors in the VFP extension register bank
VFP vector wrap-around
VFP vector stride
Restriction on vector length
Control of scalar, vector, and mixed operations
VFP directives and vector notation
Pre-UAL VFP mnemonics
Vector notation
VFPASSERT SCALAR
VFPASSERT VECTOR
Assembler User Guide
FPEXC, the floating-point exception register
| |||
| Home > VFP Programming > FPEXC, the floating-point exception register | |||
You can only access the FPEXC in privileged
software execution. It contains the following bits:
- bit[31]
Is the
EXbit. You can read it in all VFP implementations. In some implementations you might also be able to write to it.If the value is 0, the only significant state in the VFP system is the contents of the general-purpose registers plus
FPSCRandFPEXC.If the value is 1, you require implementation-specific information to save state.
- bit[30]
Is the
ENbit. You can read and write it in all VFP implementations.If the value is 1, VFP (if present) is enabled and operates normally.
If the value is 0, VFP is disabled. When it is disabled, you can read or write the
FPSIDorFPEXCregisters, but other VFP instructions are treated as Undefined Instructions.- bits[29:0]
Might be used by particular implementations of VFP. You can use the VFP instructions without accessing these bits.
You must not alter these bits except in accordance with their use in a particular implementation.
To change some bits without affecting other bits, use a read-modify-write procedure.
See also- Concepts
- Reference
The Technical Reference Manual for your VFP coprocessor.
| Copyright © 2007-2008, 2011-2012 ARM. All rights reserved. | ARM DUI 0379D |
| Non-Confidential | ID062912 |
 PDF version | |
| Home > VFP Programming > FPEXC, the floating-point exception register |
ProductsDevelopment Tools |
Hardware & Collateral |
Downloads |
Support |
Buy |
|
 |
|||
