diff --git a/libavutil/riscv/Makefile b/libavutil/riscv/Makefile index 1597154..6294b5d 100644 --- a/libavutil/riscv/Makefile +++ b/libavutil/riscv/Makefile @@ -2,4 +2,5 @@ OBJS += riscv/float_dsp_init.o \ riscv/fixed_dsp_init.o \ riscv/cpu.o RVV-OBJS += riscv/float_dsp_rvv.o \ - riscv/fixed_dsp_rvv.o + riscv/fixed_dsp_rvv.o \ + riscv/cpu_rvv.o diff --git a/libavutil/riscv/cpu.c b/libavutil/riscv/cpu.c index fa45c0a..76485fd 100644 --- a/libavutil/riscv/cpu.c +++ b/libavutil/riscv/cpu.c @@ -28,6 +28,8 @@ #define HWCAP_RV(letter) (1ul << ((letter) - 'A')) #endif +int ff_has_compliant_rvv(void); + int ff_get_cpu_flags_riscv(void) { int ret = 0; @@ -44,7 +46,7 @@ int ff_get_cpu_flags_riscv(void) ret |= AV_CPU_FLAG_RVB_ADDR | AV_CPU_FLAG_RVB_BASIC; /* The V extension implies all Zve* functional subsets */ - if (hwcap & HWCAP_RV('V')) + if ((hwcap & HWCAP_RV('V')) && ff_has_compliant_rvv()) ret |= AV_CPU_FLAG_RVV_I32 | AV_CPU_FLAG_RVV_I64 | AV_CPU_FLAG_RVV_F32 | AV_CPU_FLAG_RVV_F64; #endif diff --git a/libavutil/riscv/cpu_rvv.S b/libavutil/riscv/cpu_rvv.S new file mode 100644 index 0000000..0b25e00 --- /dev/null +++ b/libavutil/riscv/cpu_rvv.S @@ -0,0 +1,47 @@ +/****************************************************************************** + * 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 "asm.S" + +#define L(x) .L ## x + +// 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. +// The same code will work on RV32 if there is ever non-compliant rv32gcv. +func ff_has_compliant_rvv, ext=v + vsetvli zero, zero, e8, m1, ta, ma + csrr a1, vtype + li a0, 0 + blt a1, x0, L(rvv071) + li a0, 1 +L(rvv071): + ret +endfunc