From: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Date: Mon, 22 Jan 2024 16:11:02 +0000 (-0300)
Subject: target/riscv/vector_helper.c: use vlenb in HELPER(vsetvl)
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=7aa4d519cba610876abac027a5812af87c834d22;p=qemu.git

target/riscv/vector_helper.c: use vlenb in HELPER(vsetvl)

Use the new 'vlenb' CPU config to validate fractional LMUL. The original
comparison is done with 'vlen' and 'sew', both in bits. Adjust the shift
to use vlenb.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240122161107.26737-9-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---

diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c
index 908e69d073..8ee7717162 100644
--- a/target/riscv/vector_helper.c
+++ b/target/riscv/vector_helper.c
@@ -45,9 +45,16 @@ target_ulong HELPER(vsetvl)(CPURISCVState *env, target_ulong s1,
                                             xlen - 1 - R_VTYPE_RESERVED_SHIFT);
 
     if (lmul & 4) {
-        /* Fractional LMUL - check LMUL * VLEN >= SEW */
+        /*
+         * Fractional LMUL, check:
+         *
+         * VLEN * LMUL >= SEW
+         * VLEN >> (8 - lmul) >= sew
+         * (vlenb << 3) >> (8 - lmul) >= sew
+         * vlenb >> (8 - 3 - lmul) >= sew
+         */
         if (lmul == 4 ||
-            cpu->cfg.vlen >> (8 - lmul) < sew) {
+            cpu->cfg.vlenb >> (8 - 3 - lmul) < sew) {
             vill = true;
         }
     }