[FFmpeg-devel] [PATCH 8/9] lavu/riscv: add CPU flag for B bit manipulations

[Rémi Denis-Courmont]

The B extension was finally ratified in May 2024, encompassing:
- Zba (addresses),
- Zbb (basics) and
- Zbs (single bits).
It does not include Zbc (base-2 polynomials).
---
 doc/APIchanges            |  3 +++
 libavutil/cpu.c           |  1 +
 libavutil/cpu.h           |  1 +
 libavutil/riscv/cpu.c     | 13 +++++++++++++
 libavutil/tests/cpu.c     |  1 +
 tests/checkasm/checkasm.c |  1 +
 6 files changed, 20 insertions(+)

diff --git a/doc/APIchanges b/doc/APIchanges
index 5751216b24..0061b084b8 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -2,6 +2,9 @@ The last version increases of all libraries were on 2024-03-07
 
 API changes, most recent first:
 
+2024-07-22 - xxxxxxxxx - lavu 59.18.100 - cpu.h
+  Add AV_CPU_FLAG_RVB.
+
 2024-07-xx - xxxxxxxxxx - lavf 61 - avformat.h
   Deprecate avformat_transfer_internal_stream_timing_info()
   and av_stream_get_codec_timebase() without replacement.
diff --git a/libavutil/cpu.c b/libavutil/cpu.c
index 9ac2f01c20..17afe8858a 100644
--- a/libavutil/cpu.c
+++ b/libavutil/cpu.c
@@ -186,6 +186,7 @@ int av_parse_cpu_caps(unsigned *flags, const char *s)
         { "rvi",      NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_CPU_FLAG_RVI      },    .unit = "flags" },
         { "rvf",      NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_CPU_FLAG_RVF      },    .unit = "flags" },
         { "rvd",      NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_CPU_FLAG_RVD      },    .unit = "flags" },
+        { "rvb",      NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_CPU_FLAG_RVB      },    .unit = "flags" },
         { "zve32x",   NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_CPU_FLAG_RVV_I32  },    .unit = "flags" },
         { "zve32f",   NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_CPU_FLAG_RVV_F32  },    .unit = "flags" },
         { "zve64x",   NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_CPU_FLAG_RVV_I64  },    .unit = "flags" },
diff --git a/libavutil/cpu.h b/libavutil/cpu.h
index a25901433e..9f419aae02 100644
--- a/libavutil/cpu.h
+++ b/libavutil/cpu.h
@@ -92,6 +92,7 @@
 #define AV_CPU_FLAG_RVB_ADDR     (1 << 8) ///< Address bit-manipulations
 #define AV_CPU_FLAG_RV_ZVBB      (1 << 9) ///< Vector basic bit-manipulations
 #define AV_CPU_FLAG_RV_MISALIGNED (1 <<10) ///< Fast misaligned accesses
+#define AV_CPU_FLAG_RVB          (1 <<11) ///< B (bit manipulations)
 
 /**
  * Return the flags which specify extensions supported by the CPU.
diff --git a/libavutil/riscv/cpu.c b/libavutil/riscv/cpu.c
index 04ac404bbf..e035f4b024 100644
--- a/libavutil/riscv/cpu.c
+++ b/libavutil/riscv/cpu.c
@@ -72,6 +72,12 @@ int ff_get_cpu_flags_riscv(void)
 #ifdef RISCV_HWPROBE_EXT_ZBB
         if (pairs[1].value & RISCV_HWPROBE_EXT_ZBB)
             ret |= AV_CPU_FLAG_RVB_BASIC;
+#if defined (RISCV_HWPROBE_EXT_ZBA) && defined (RISCV_HWPROBE_EXT_ZBS)
+        if ((pairs[1].value & RISCV_HWPROBE_EXT_ZBA) &&
+            (pairs[1].value & RISCV_HWPROBE_EXT_ZBB) &&
+            (pairs[1].value & RISCV_HWPROBE_EXT_ZBS))
+            ret |= AV_CPU_FLAG_RVB;
+#endif
 #endif
 #ifdef RISCV_HWPROBE_EXT_ZVBB
         if (pairs[1].value & RISCV_HWPROBE_EXT_ZVBB)
@@ -94,6 +100,9 @@ int ff_get_cpu_flags_riscv(void)
             ret |= AV_CPU_FLAG_RVF;
         if (hwcap & HWCAP_RV('D'))
             ret |= AV_CPU_FLAG_RVD;
+        if (hwcap & HWCAP_RV('B'))
+            ret |= AV_CPU_FLAG_RVB_ADDR | AV_CPU_FLAG_RVB_BASIC |
+                   AV_CPU_FLAG_RVB;
 
         /* The V extension implies all Zve* functional subsets */
         if (hwcap & HWCAP_RV('V'))
@@ -118,6 +127,10 @@ int ff_get_cpu_flags_riscv(void)
 #ifdef __riscv_zbb
     ret |= AV_CPU_FLAG_RVB_BASIC;
 #endif
+#if defined (__riscv_b) || \
+    (defined (__riscv_zba) && defined (__riscv_zbb) && defined (__riscv_zbs))
+    ret |= AV_CPU_FLAG_RVB;
+#endif
 
     /* If RV-V is enabled statically at compile-time, check the details. */
 #ifdef __riscv_vector
diff --git a/libavutil/tests/cpu.c b/libavutil/tests/cpu.c
index 02b98682e3..b4b11775d8 100644
--- a/libavutil/tests/cpu.c
+++ b/libavutil/tests/cpu.c
@@ -90,6 +90,7 @@ static const struct {
     { AV_CPU_FLAG_RVD,       "rvd"        },
     { AV_CPU_FLAG_RVB_ADDR,  "zba"        },
     { AV_CPU_FLAG_RVB_BASIC, "zbb"        },
+    { AV_CPU_FLAG_RVB,       "rvb"        },
     { AV_CPU_FLAG_RVV_I32,   "zve32x"     },
     { AV_CPU_FLAG_RVV_F32,   "zve32f"     },
     { AV_CPU_FLAG_RVV_I64,   "zve64x"     },
diff --git a/tests/checkasm/checkasm.c b/tests/checkasm/checkasm.c
index de0024099a..016f2329b0 100644
--- a/tests/checkasm/checkasm.c
+++ b/tests/checkasm/checkasm.c
@@ -295,6 +295,7 @@ static const struct {
     { "RVD",      "rvd",      AV_CPU_FLAG_RVD },
     { "RVBaddr",  "rvb_a",    AV_CPU_FLAG_RVB_ADDR },
     { "RVBbasic", "rvb_b",    AV_CPU_FLAG_RVB_BASIC },
+    { "RVB",      "rvb",      AV_CPU_FLAG_RVB },
     { "RVVi32",   "rvv_i32",  AV_CPU_FLAG_RVV_I32 },
     { "RVVf32",   "rvv_f32",  AV_CPU_FLAG_RVV_F32 },
     { "RVVi64",   "rvv_i64",  AV_CPU_FLAG_RVV_I64 },
-- 
2.45.2