Source code
Revision control
Copy as Markdown
Other Tools
/******************************************************************************
* Copyright © 2018, VideoLAN and dav1d authors
* Copyright © 2024, Nathan Egge
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*****************************************************************************/
#include "src/riscv/asm.S"
// This function detects non-compliant RVV 0.7.1 hardware which reports support
// for the V extension through HWCAP, by intentionally setting tail and mask
// agnostic vector configurations that were only introduced in RVV 0.9 spec.
// Existing non-compliant (pre RVV 1.0) hardware will set the VILL bit in VTYPE
// (indicating an illegal vector configuration) which is stored in the XLEN-1
// bit position, thus a simple sign check is sufficient for detection.
// This work around is inexpensive and harmless on compliant hardware, but we
// should still consider removing it once all non-compliant RVV 0.7.1 hardware
// is out of service.
function has_compliant_rvv, export=1, ext=v
vsetvli t0, zero, e8, m1, ta, ma
csrr a0, vtype
sgtz a0, a0
ret
endfunc
function get_vlenb, export=1
csrr a0, vlenb
ret
endfunc