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VFPASSERT SCALAR
VFPASSERT VECTOR
Assembler User Guide
VFPASSERT SCALAR
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| Home > VFP Programming > VFPASSERT SCALAR | |||
The VFPASSERT SCALAR directive informs the assembler
that following VFP instructions are in scalar mode. This forces
the instruction syntax to be scalar.
SyntaxUse the VFPASSERT SCALAR directive to mark the
end of any block of code where the VFP mode is VECTOR.
Place the VFPASSERT SCALAR directive immediately
after the instruction where the change occurs. This is usually an FMXR instruction,
but might be a BL instruction.
If a function expects the VFP to be in vector mode on exit,
place a VFPASSERT SCALAR directive immediately after
the last instruction. Such a function would not be AAPCS compliant.
Note
This directive does not generate any code. It is only an assertion by the programmer. The assembler produces error messages if any such assertions are inconsistent with each other, or with any vector notation in VFP data processing instructions.
The assembler faults vector notation in VFP data processing
instructions following a VFPASSERT SCALAR directive,
even if the vector length is 1.
VFPASSERT SCALAR ; scalar mode
faddd d4, d4, d0 ; okay
fadds s4<3>, s8<3>, s0 ; ERROR, vectors in scalar mode
fabss s24<1>, s28<1> ; ERROR, vectors in scalar mode
; (even though length==1)
| Copyright © 2007-2008, 2011-2012 ARM. All rights reserved. | ARM DUI 0379D |
| Non-Confidential | ID062912 |
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| Home > VFP Programming > VFPASSERT SCALAR |
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