[FFmpeg-devel] [PATCH 03/10] riscv: float vector-scalar multiplication with RVV

[remi at remlab.net]

From: Rémi Denis-Courmont <remi at remlab.net>

This is based on existing code from the VLC git tree with two minor
changes to account for the different function prototypes.
---
 libavutil/float_dsp.c            |  2 ++
 libavutil/float_dsp.h            |  1 +
 libavutil/riscv/Makefile         |  4 ++-
 libavutil/riscv/float_dsp_init.c | 41 +++++++++++++++++++++
 libavutil/riscv/float_dsp_rvv.S  | 62 ++++++++++++++++++++++++++++++++
 5 files changed, 109 insertions(+), 1 deletion(-)
 create mode 100644 libavutil/riscv/float_dsp_init.c
 create mode 100644 libavutil/riscv/float_dsp_rvv.S

diff --git a/libavutil/float_dsp.c b/libavutil/float_dsp.c
index 8676c8b0f8..742dd679d2 100644
--- a/libavutil/float_dsp.c
+++ b/libavutil/float_dsp.c
@@ -156,6 +156,8 @@ av_cold AVFloatDSPContext *avpriv_float_dsp_alloc(int bit_exact)
     ff_float_dsp_init_arm(fdsp);
 #elif ARCH_PPC
     ff_float_dsp_init_ppc(fdsp, bit_exact);
+#elif ARCH_RISCV
+    ff_float_dsp_init_riscv(fdsp);
 #elif ARCH_X86
     ff_float_dsp_init_x86(fdsp);
 #elif ARCH_MIPS
diff --git a/libavutil/float_dsp.h b/libavutil/float_dsp.h
index 9c664592bd..7cad9fc622 100644
--- a/libavutil/float_dsp.h
+++ b/libavutil/float_dsp.h
@@ -205,6 +205,7 @@ float avpriv_scalarproduct_float_c(const float *v1, const float *v2, int len);
 void ff_float_dsp_init_aarch64(AVFloatDSPContext *fdsp);
 void ff_float_dsp_init_arm(AVFloatDSPContext *fdsp);
 void ff_float_dsp_init_ppc(AVFloatDSPContext *fdsp, int strict);
+void ff_float_dsp_init_riscv(AVFloatDSPContext *fdsp);
 void ff_float_dsp_init_x86(AVFloatDSPContext *fdsp);
 void ff_float_dsp_init_mips(AVFloatDSPContext *fdsp);
 
diff --git a/libavutil/riscv/Makefile b/libavutil/riscv/Makefile
index 1f818043dc..6bf8243e8d 100644
--- a/libavutil/riscv/Makefile
+++ b/libavutil/riscv/Makefile
@@ -1 +1,3 @@
-OBJS += riscv/cpu.o
+OBJS += riscv/cpu.o \
+        riscv/float_dsp_init.o \
+        riscv/float_dsp_rvv.o
diff --git a/libavutil/riscv/float_dsp_init.c b/libavutil/riscv/float_dsp_init.c
new file mode 100644
index 0000000000..279412c036
--- /dev/null
+++ b/libavutil/riscv/float_dsp_init.c
@@ -0,0 +1,41 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdint.h>
+
+#include "libavutil/attributes.h"
+#include "libavutil/cpu.h"
+#include "libavutil/float_dsp.h"
+
+void ff_vector_fmul_scalar_rvv(float *dst, const float *src, float mul,
+                                int len);
+
+void ff_vector_dmul_scalar_rvv(double *dst, const double *src, double mul,
+                                int len);
+
+av_cold void ff_float_dsp_init_riscv(AVFloatDSPContext *fdsp)
+{
+    int flags = av_get_cpu_flags();
+
+    if (flags & AV_CPU_FLAG_ZVE32F) {
+        fdsp->vector_fmul_scalar = ff_vector_fmul_scalar_rvv;
+
+        if (flags & AV_CPU_FLAG_ZVE64D)
+            fdsp->vector_dmul_scalar = ff_vector_dmul_scalar_rvv;
+    }
+}
diff --git a/libavutil/riscv/float_dsp_rvv.S b/libavutil/riscv/float_dsp_rvv.S
new file mode 100644
index 0000000000..98d06c6d07
--- /dev/null
+++ b/libavutil/riscv/float_dsp_rvv.S
@@ -0,0 +1,62 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "config.h"
+#include "asm.S"
+
+        .option  arch, +v
+
+// (a0) = (a1) * fa0 [0..a2-1]
+func ff_vector_fmul_scalar_rvv
+#if defined (__riscv_float_abi_soft)
+        fmv.w.x  fa0, a2
+        mv       a2, a3
+#endif
+
+1:      vsetvli  t0, a2, e32, m8, ta, ma
+        slli     t1, t0, 2
+        vle32.v  v16, (a1)
+        add      a1, a1, t1
+        vfmul.vf v16, v16, fa0
+        sub      a2, a2, t0
+        vse32.v  v16, (a0)
+        add      a0, a0, t1
+        bnez     a2, 1b
+
+        ret
+endfunc
+
+// (a0) = (a1) * fa0 [0..a2-1]
+func ff_vector_dmul_scalar_rvv
+#if defined (__riscv_float_abi_soft) || defined (__riscv_float_abi_single)
+        fmv.d.x  fa0, a2
+        mv       a2, a3
+#endif
+
+1:      vsetvli  t0, a2, e64, m8, ta, ma
+        slli     t1, t0, 3
+        vle64.v  v16, (a1)
+        add      a1, a1, t1
+        vfmul.vf v16, v16, fa0
+        sub      a2, a2, t0
+        vse64.v  v16, (a0)
+        add      a0, a0, t1
+        bnez     a2, 1b
+
+        ret
+endfunc
-- 
2.37.2