[PATCH v10 32/77] target/riscv: rvv-1.0: iota instruction

[frank . chang]

From: Frank Chang <frank.ch...@sifive.com>

Signed-off-by: Frank Chang <frank.ch...@sifive.com>
Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
Reviewed-by: Alistair Francis <alistair.fran...@wdc.com>
---
 target/riscv/insn32.decode              |  2 +-
 target/riscv/insn_trans/trans_rvv.c.inc | 10 ++++++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/target/riscv/insn32.decode b/target/riscv/insn32.decode
index d139c0aade7..3ac5162aeb7 100644
--- a/target/riscv/insn32.decode
+++ b/target/riscv/insn32.decode
@@ -632,7 +632,7 @@ vfirst_m        010000 . ..... 10001 010 ..... 1010111 
@r2_vm
 vmsbf_m         010100 . ..... 00001 010 ..... 1010111 @r2_vm
 vmsif_m         010100 . ..... 00011 010 ..... 1010111 @r2_vm
 vmsof_m         010100 . ..... 00010 010 ..... 1010111 @r2_vm
-viota_m         010110 . ..... 10000 010 ..... 1010111 @r2_vm
+viota_m         010100 . ..... 10000 010 ..... 1010111 @r2_vm
 vid_v           010110 . 00000 10001 010 ..... 1010111 @r1_vm
 vext_x_v        001100 1 ..... ..... 010 ..... 1010111 @r
 vmv_s_x         001101 1 00000 ..... 110 ..... 1010111 @r2
diff --git a/target/riscv/insn_trans/trans_rvv.c.inc 
b/target/riscv/insn_trans/trans_rvv.c.inc
index 9206e6f06c8..80cbf0cadb8 100644
--- a/target/riscv/insn_trans/trans_rvv.c.inc
+++ b/target/riscv/insn_trans/trans_rvv.c.inc
@@ -2757,12 +2757,18 @@ GEN_M_TRANS(vmsbf_m)
 GEN_M_TRANS(vmsif_m)
 GEN_M_TRANS(vmsof_m)
 
-/* Vector Iota Instruction */
+/*
+ * Vector Iota Instruction
+ *
+ * 1. The destination register cannot overlap the source register.
+ * 2. If masked, cannot overlap the mask register ('v0').
+ * 3. An illegal instruction exception is raised if vstart is non-zero.
+ */
 static bool trans_viota_m(DisasContext *s, arg_viota_m *a)
 {
     if (require_rvv(s) &&
         vext_check_isa_ill(s) &&
-        require_noover(a->rd, s->lmul, a->rs2, 0) &&
+        !is_overlapped(a->rd, 1 << MAX(s->lmul, 0), a->rs2, 1) &&
         require_vm(a->vm, a->rd) &&
         require_align(a->rd, s->lmul)) {
         uint32_t data = 0;
-- 
2.25.1