Cortex-A8 R2P2.pdf - ARM Information Center

NEON and VFP Programmer’s ModelFCVTDS and FCVTSD.Fixed-point instructionsFSHTOS/D, FSCTOS/D, FUHTOS/D, FULTOS/D, FTOSHS/D, FTOSLS/D, FTOUHS/D,and FTOULS/D.Short vector-only instructionsVector-only instructions require that the value in the LEN field is nonzero, and that thedestination and Fm registers are not in bank 0.Example 13-2 shows the iterations of the following short vector instruction:FMACS S16, S0, S8In the example, the LEN field contains b011, selecting a vector length of four iterations,and the STRIDE field contains b00, selecting a vector stride of one.Example 13-2 Short vector instructionFMACS S16, S0, S8FMACS S17, S1, S9FMACS S18, S2, S10FMACS S19, S3, S11; 1st iteration; 2nd iteration; 3rd iteration; 4th and last iterationShort vector instructions with scalar sourceThe VFPv3 architecture enables a vector to be operated on by a scalar operand. Thedestination must be a vector, that is, not in bank 0, and the Fm operand must be inbank 0.Example 13-3 shows the iterations of the following short vector instruction with a scalarsource:FMULD D12, D8, D2In the example, the LEN field contains b001, selecting a vector length of two iterations,and the STRIDE field contains b00, selecting a vector stride of one.Example 13-3 Short vector instruction with scalar sourceFMULD D12, D8, D2FMULD D13, D9, D2; 1st iteration; 2nd and last iterationARM DDI 0344E Copyright © 2006-2008 ARM Limited. All rights reserved. 13-9