diff --git a/disas/riscv.c b/disas/riscv.c
index 54455aaaa8..d6b0fbe5e8 100644
--- a/disas/riscv.c
+++ b/disas/riscv.c
@@ -1014,6 +1014,7 @@ static const char rv_vreg_name_sym[32][4] = {
 #define rv_fmt_rd_offset              "O\t0,o"
 #define rv_fmt_rd_rs1_rs2             "O\t0,1,2"
 #define rv_fmt_frd_rs1                "O\t3,1"
+#define rv_fmt_frd_frs1               "O\t3,4"
 #define rv_fmt_rd_frs1                "O\t0,4"
 #define rv_fmt_rd_frs1_frs2           "O\t0,4,5"
 #define rv_fmt_frd_frs1_frs2          "O\t3,4,5"
@@ -1580,15 +1581,15 @@ const rv_opcode_data opcode_data[] = {
     { "snez", rv_codec_r, rv_fmt_rd_rs2, NULL, 0, 0, 0 },
     { "sltz", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
     { "sgtz", rv_codec_r, rv_fmt_rd_rs2, NULL, 0, 0, 0 },
-    { "fmv.s", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
-    { "fabs.s", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
-    { "fneg.s", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
-    { "fmv.d", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
-    { "fabs.d", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
-    { "fneg.d", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
-    { "fmv.q", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
-    { "fabs.q", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
-    { "fneg.q", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
+    { "fmv.s", rv_codec_r, rv_fmt_frd_frs1, NULL, 0, 0, 0 },
+    { "fabs.s", rv_codec_r, rv_fmt_frd_frs1, NULL, 0, 0, 0 },
+    { "fneg.s", rv_codec_r, rv_fmt_frd_frs1, NULL, 0, 0, 0 },
+    { "fmv.d", rv_codec_r, rv_fmt_frd_frs1, NULL, 0, 0, 0 },
+    { "fabs.d", rv_codec_r, rv_fmt_frd_frs1, NULL, 0, 0, 0 },
+    { "fneg.d", rv_codec_r, rv_fmt_frd_frs1, NULL, 0, 0, 0 },
+    { "fmv.q", rv_codec_r, rv_fmt_frd_frs1, NULL, 0, 0, 0 },
+    { "fabs.q", rv_codec_r, rv_fmt_frd_frs1, NULL, 0, 0, 0 },
+    { "fneg.q", rv_codec_r, rv_fmt_frd_frs1, NULL, 0, 0, 0 },
     { "beqz", rv_codec_sb, rv_fmt_rs1_offset, NULL, 0, 0, 0 },
     { "bnez", rv_codec_sb, rv_fmt_rs1_offset, NULL, 0, 0, 0 },
     { "blez", rv_codec_sb, rv_fmt_rs2_offset, NULL, 0, 0, 0 },
@@ -1647,7 +1648,7 @@ const rv_opcode_data opcode_data[] = {
     { "clzw", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
     { "ctzw", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
     { "cpopw", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
-    { "slli.uw", rv_codec_i_sh5, rv_fmt_rd_rs1_imm, NULL, 0, 0, 0 },
+    { "slli.uw", rv_codec_i_sh6, rv_fmt_rd_rs1_imm, NULL, 0, 0, 0 },
     { "add.uw", rv_codec_r, rv_fmt_rd_rs1_rs2, NULL, 0, 0, 0 },
     { "rolw", rv_codec_r, rv_fmt_rd_rs1_rs2, NULL, 0, 0, 0 },
     { "rorw", rv_codec_r, rv_fmt_rd_rs1_rs2, NULL, 0, 0, 0 },
@@ -2617,10 +2618,10 @@ static void decode_inst_opcode(rv_decode *dec, rv_isa isa)
             switch (((inst >> 12) & 0b111)) {
             case 0: op = rv_op_addiw; break;
             case 1:
-                switch (((inst >> 25) & 0b1111111)) {
+                switch (((inst >> 26) & 0b111111)) {
                 case 0: op = rv_op_slliw; break;
-                case 4: op = rv_op_slli_uw; break;
-                case 48:
+                case 2: op = rv_op_slli_uw; break;
+                case 24:
                     switch ((inst >> 20) & 0b11111) {
                     case 0b00000: op = rv_op_clzw; break;
                     case 0b00001: op = rv_op_ctzw; break;