VMRS and VMSR

Transfer contents between an ARM register and a VFP system register.

Show/hideSyntax

VMRS{cond} Rd, extsysreg
VMSR{cond} extsysreg, Rd

where:

cond

is an optional condition code.

extsysreg

is the VFP system register, usually FPSCR, FPSID, or FPEXC.

Rd

is the ARM register. Rd must not be PC.

It can be APSR_nzcv, if extsysreg is FPSCR. In this case, the floating-point status flags are transferred into the corresponding flags in the ARM APSR.

Show/hideUsage

The VMRS instruction transfers the contents of extsysreg into Rd.

The VMSR instruction transfers the contents of Rd into extsysreg.

Note

These instructions stall the ARM until all current VFP operations complete.

Show/hideExamples

    VMRS    r2,FPCID
    VMRS    APSR_nzcv, FPSCR     ; transfer FP status register to ARM APSR
    VMSR    FPSCR, r4

Show/hideSee also

Concepts

Using the Assembler:

Reference:
Copyright © 2011 ARM. All rights reserved.ARM DUI 0588A
Non-ConfidentialID061811