Cortex-A8 R2P2.pdf - ARM Information Center

NEON and VFP Programmer’s Model13.2 General-purpose registersThe NEON and VFP coprocessor shares the same register bank. This is distinct fromthe ARM register bank.You can reference the NEON and VFP register bank using three explicitly aliasedviews, as described in the following sections.Figure 13-1 on page 13-5 shows the three views of the register bank and the way theword, doubleword, and quadword registers overlap.13.2.1 NEON views of the register bankNEON views the register bank as:• Sixteen 128-bit quadword registers, Q0-Q15.• Thirty-two 64-bit doubleword registers, D0-D31. This view is also available inVFP.• A combination of these 128-bit and 64-bit registers, Q0-Q15 and D0-D31.13.2.2 VFP views of the register bankIn VFP, you can view the register bank as:• Thirty-two 64-bit doubleword registers, D0-D31. This view is also available inNEON.• Thirty-two 32-bit single word registers, S0-S31. Only half of the register bank isaccessible in this view.• A combination of these 128-bit and 64-bit registers, D0-D31 and S0-S31.13-4 Copyright © 2006-2008 ARM Limited. All rights reserved. ARM DDI 0344E