Hi,
>> To use VFP/NEON instruction, what option do I specify to armv7 clang?
>
> You'll also need "-mfloat-abi=softfp". Note that this is soon going
> to be the default in -current. At some point in the future we'll
> switch the default to "-mfloat-abi=hardfp" which is inompatible with
> "-mfloat-abi=softfp". It is probably a bad idea to push changes that
> explicitly set -mfloat-abi upstream.
Adding -mfloat-abi=softfp option solved the problem. Thanks.
I tried with that option before sending this question to ML
but the disassembled code of objdump-2.17 confused me.
1c44: ed900a2a flds s0, [r0, #168]
1c48: e08f0001 add r0, pc, r1
1c4c: ed901a02 flds s2, [r0, #8]
1c50: eef80bc0 cdp 11, 15, cr0, cr8, cr0, {6}
1c54: eef81bc1 cdp 11, 15, cr1, cr8, cr1, {6}
1c58: eec10ba0 cdp 11, 12, cr0, cr1, cr0, {5}
Same binary with objdump-2.27.
1c44: ed900a2a vldr s0, [r0, #168] ; 0xa8
1c48: e08f0001 add r0, pc, r1
1c4c: ed901a02 vldr s2, [r0, #8]
1c50: eef80bc0 vcvt.f64.s32 d16, s0
1c54: eef81bc1 vcvt.f64.s32 d17, s2
1c58: eec10ba0 vdiv.f64 d16, d17, d16
I thought the first letter of NEON/VFP instruction is "v",
so I misunderstood that these instruction is not available...
Best regards,
--
SASANO Takayoshi (JG1UAA) <[email protected]>
