diff --git a/src/jit/dis_loongarch64.lua b/src/jit/dis_loongarch64.lua
index 96a2b322f..a334445e3 100644
--- a/src/jit/dis_loongarch64.lua
+++ b/src/jit/dis_loongarch64.lua
@@ -23,8 +23,8 @@ local lshift, rshift, arshift = bit.lshift, bit.rshift, bit.arshift
 -- Opcode maps
 ------------------------------------------------------------------------------
 
-local map_18_0 = { -- 18-20:0, 10-17
-  shift = 10, mask = 255,
+local map_zero_31_15 = { -- [31:15] = 0
+  shift = 10, mask = 0xff,
   [4] = "clo.wDJ",
   [5] = "clz.wDJ",
   [6] = "cto.wDJ",
@@ -47,189 +47,57 @@ local map_18_0 = { -- 18-20:0, 10-17
   [23] = "ext.w.bDJ",
 }
 
-local map_18_4 = { -- 18-20:4, 15-17
-  shift = 15, mask = 7,
-  [0] = "add.wDJK",
-  [1] = "add.dDJK",
-  [2] = "sub.wDJK",
-  [3] = "sub.dDJK",
-  [4] = "sltDJK",
-  [5] = "sltuDJK",
-  [6] = "maskeqzDJK",
-  [7] = "masknezDJK",
-}
-
-local map_18_5 = { -- 18-20:5, 15-17
-  shift = 15, mask = 7,
-  [0] = "norDJK",
-  [1] = "andDJK",
-  [2] = "orDJK",
-  [3] = "xorDJK",
-  [4] = "ornDJK",
-  [5] = "andnDJK",
-  [6] = "sll.wDJK",
-  [7] = "srl.wDJK",
-}
-
-local map_18_6 = { -- 18-20:6, 15-17
-  shift = 15, mask = 7,
-  [0] = "sra.wDJK",
-  [1] = "sll.dDJK",
-  [2] = "srl.dDJK",
-  [3] = "sra.dDJK",
-  [6] = "rotr.wDJK",
-  [7] = "rotr.dDJK",
-}
-
-local map_18_7 = { -- 18-20:7, 15-17
-  shift = 15, mask = 7,
-  [0] = "mul.wDJK",
-  [1] = "mulh.wDJK",
-  [2] = "mulh.wuDJK",
-  [3] = "mul.dDJK",
-  [4] = "mulh.dDJK",
-  [5] = "mulh.duDJK",
-  [6] = "mulw.d.wDJK",
-  [7] = "mulw.d.wuDJK",
-}
-
-local map_farith2 = {
-  shift = 10, mask = 31,
-  [1] = "fabs.sFG",
-  [2] = "fabs.dFG",
-  [5] = "fneg.sFG",
-  [6] = "fneg.dFG",
-  [9] = "flogb.sFG",
-  [10] = "flogb.dFG",
-  [13] = "fclass.sFG",
-  [14] = "fclass.dFG",
-  [17] = "fsqrt.sFG",
-  [18] = "fsqrt.dFG",
-  [21] = "frecip.sFG",
-  [22] = "frecip.dFG",
-  [25] = "frsqrt.sFG",
-  [26] = "frsqrt.dFG",
-  [29] = "frecipe.sFG",
-  [30] = "frecipe.dFG",
-  [33] = "frsqrte.sFG",
-  [34] = "frsqrte.dFG",
-}
-
-local map_fmov = {
-  shift = 10, mask = 31,
-  [5] = "fmov.sFG",
-  [6] = "fmov.dFG",
-  [9] = "movgr2fr.wFJ",
-  [10] = "movgr2fr.dFJ",
-  [11] = "movgr2frh.wFJ",
-  [13] = "movfr2gr.sDG",
-  [14] = "movfr2gr.dDG",
-  [15] = "movfrh2gr.sDG",
-  [16] = "movgr2fcsrSJ",
-  [18] = "movfcsr2grDR",
-  [20] = { shift = 3, mask = 3, [0] = "movfr2cfEG", },
-  [21] = { shift = 8, mask = 3, [0] = "movcf2frFA", },
-  [22] = { shift = 3, mask = 3, [0] = "movgr2cfEJ", },
-  [23] = { shift = 8, mask = 3, [0] = "movcf2grDA", },
-}
-
-local map_fconvert = { -- 15-20: 110010
-  shift = 10, mask = 31,
-  [6] = "fcvt.s.dFG",	[9] = "fcvt.d.sFG",
-}
-
-local map_fconvert1 = { -- 15-20: 110100
-  shift = 10, mask = 31,
-  [1] = "ftintrm.w.sFG",
-  [2] = "ftintrm.w.dFG",
-  [9] = "ftintrm.l.sFG",
-  [10] = "ftintrm.l.dFG",
-  [17] = "ftintrp.w.sFG",
-  [18] = "ftintrp.w.dFG",
-  [25] = "ftintrp.l.sFG",
-  [26] = "ftintrp.l.dFG",
-}
-
-local map_fconvert2 = { -- 15-20: 110101
-  shift = 10, mask = 31,
-  [1] = "ftintrz.w.sFG",
-  [2] = "ftintrz.w.dFG",
-  [9] = "ftintrz.l.sFG",
-  [10] = "ftintrz.l.dFG",
-  [17] = "ftintrne.w.sFG",
-  [18] = "ftintrne.w.dFG",
-  [25] = "ftintrne.l.sFG",
-  [26] = "ftintrne.l.dFG",
-}
-
-local map_fconvert3 = { -- 15-20: 110110
-  shift = 10, mask = 31,
-  [1] = "ftint.w.sFG",
-  [2] = "ftint.w.dFG",
-  [9] = "ftint.l.sFG",
-  [10] = "ftint.l.dFG",
-}
-
-local map_fconvert4 = { -- 15-20: 111010
-  shift = 10, mask = 31,
-  [4] = "ffint.s.wFG",
-  [6] =  "ffint.s.lFG",
-  [8] = "ffint.d.wFG",
-  [10] = "ffint.d.lFG",
-}
-
-local map_fconvert5 = { -- 15-20: 111100
-  shift = 10, mask = 31,
-  [17] = "frint.sFG",
-  [18] = "frint.dFG",
-}
-
-local map_farith = { -- 22-25:4, 15-21
-  shift = 15, mask = 127,
-  [1] = "fadd.sFGH",
-  [2] = "fadd.dFGH",
-  [5] = "fsub.sFGH",
-  [6] = "fsub.dFGH",
-  [9] = "fmul.sFGH",
-  [10] = "fmul.dFGH",
-  [13] = "fdiv.sFGH",
-  [14] = "fdiv.dFGH",
-  [17] = "fmax.sFGH",
-  [18] = "fmax.dFGH",
-  [21] = "fmin.sFGH",
-  [22] = "fmin.dFGH",
-  [25] = "fmaxa.sFGH",
-  [26] = "fmaxa.dFGH",
-  [29] = "fmina.sFGH",
-  [30] = "fmina.dFGH",
-  [33] = "fscaleb.sFGH",
-  [34] = "fscaleb.dFGH",
-  [37] = "fcopysign.sFGH",
-  [38] = "fcopysign.dFGH",
-  [40] = map_farith2, [41] = map_fmov,
-  [50] = map_fconvert, [52] = map_fconvert1,
-  [53] = map_fconvert2, [54] = map_fconvert3,
-  [58] = map_fconvert4, [60] = map_fconvert5,
-}
-
-local map_21_0 = { --21st:0, 18-20
-  shift = 18, mask = 7,
-  [0] = map_18_0,
-  [1] = { shift = 17, mask = 1, [0] = "alsl.wDJKQ", "alsl.wuDJKQ", },
-  [2] = {shift = 17, mask = 1, [0] = "bytepick.wDJKQ", },
+local map_zero_31_20 = { -- [31:20] = 0
+  shift = 18, mask = 0x3,
+  [0] = map_zero_31_15,
+  [1] = {
+    shift = 17, mask = 0x1,
+    [0] = "alsl.wDJKQ", "alsl.wuDJKQ",
+  },
+  [2] = "bytepick.wDJKQ",
   [3] = "bytepick.dDJKB",
-  [4] = map_18_4,
-  [5] = map_18_5,
-  [6] = map_18_6,
-  [7] = map_18_7,
 }
 
-local map_21_1 = { --21st:1, 22nd:0, 15-20
-  shift = 21, mask = 1,
+local map_zero_31_22 = { -- [31:22] = 0
+  shift = 20, mask = 0x3,
+  [0] = map_zero_31_20,
   [1] = {
-    shift = 18, mask = 7,
+    shift = 15, mask = 0x1f,
+    [0] = "add.wDJK",
+    [1] = "add.dDJK",
+    [2] = "sub.wDJK",
+    [3] = "sub.dDJK",
+    [4] = "sltDJK",
+    [5] = "sltuDJK",
+    [6] = "maskeqzDJK",
+    [7] = "masknezDJK",
+    [8] = "norDJK",
+    [9] = "andDJK",
+    [10] = "orDJK",
+    [11] = "xorDJK",
+    [12] = "ornDJK",
+    [13] = "andnDJK",
+    [14] = "sll.wDJK",
+    [15] = "srl.wDJK",
+    [16] = "sra.wDJK",
+    [17] = "sll.dDJK",
+    [18] = "srl.dDJK",
+    [19] = "sra.dDJK",
+    [22] = "rotr.wDJK",
+    [23] = "rotr.dDJK",
+    [24] = "mul.wDJK",
+    [25] = "mulh.wDJK",
+    [26] = "mulh.wuDJK",
+    [27] = "mul.dDJK",
+    [28] = "mulh.dDJK",
+    [29] = "mulh.duDJK",
+    [30] = "mulw.d.wDJK",
+    [31] = "mulw.d.wuDJK",
+  },
+  [2] = {
+    shift = 19, mask = 0x1,
     [0] = {
-      shift = 15, mask = 7,
+      shift = 15, mask = 0x1f,
       [0] = "div.wDJK",
       [1] = "mod.wDJK",
       [2] = "div.wuDJK",
@@ -240,230 +108,382 @@ local map_21_1 = { --21st:1, 22nd:0, 15-20
       [7] = "mod.duDJK",
     },
     [1] = {
-      shift = 18, mask = 7,
-      [0] = "crc.w.b.wDJK",
-      [1] = "crc.w.h.wDJK",
-      [2] = "crc.w.w.wDJK",
-      [3] = "crc.w.d.wDJK",
-      [4] = "crcc.w.b.wDJK",
-      [5] = "crcc.w.h.wDJK",
-      [6] = "crcc.w.w.wDJK",
-      [7] = "crcc.w.d.wDJK",
-    },
-    [2] = {
-      shift = 15, mask = 7,
-      [4] = breakC, [6] = syscallC,
+      shift = 17, mask = 0x7,
+      [6] = "alsl.dDJKQ",
     },
-    [3] = { shift = 17, mask = 1, [0] = "alsl.dDJKQ", },
   },
 }
 
-local map_22_0 = {
-  shift = 21, mask = 1,
-  [0] = map_21_0,
-  [1] = map_21_1,
-}
-
-local map_shift = { -- 22nd:1, 21st:0
-  shift = 16, mask = 31,
-  [0] = { shift = 15, mask = 1, [1] = "slli.wDJU", },
-  [1] = "slli.dDJV",
-  [4] = { shift = 15, mask = 1, [1] = "srli.wDJU", },
-  [5] = "srli.dDJV",
-  [8] = { shift = 15, mask = 1, [1] = "srai.wDJU", },
-  [9] = "srai.dDJV",
-  [12] = { shift = 15, mask = 1, [1] = "rotri.wDJU", },
-  [13] = "rotri.dDJV",
-}
-
-local map_22_1 = { -- 22nd:1
-  shift = 21, mask = 1,
-  [0] = map_shift,
-  [1] = { shift = 15, mask = 1, [0] = "bstrins.wDJMU", [1] = "bstrpick.wDJMU", },
-}
-
-local map_26_0 = {
-  shift = 22, mask = 15,
-  [0] = map_22_0,
-  [1] = map_22_1,
+local map_zero_31_23 = { -- [31:24] = 0
+  shift = 22, mask = 0x3,
+  [0] = map_zero_31_22,
+  [1] = {
+    shift = 21, mask = 0x1,
+    [0] = {
+      shift = 16, mask = 0x1,
+      [0] = {
+        shift = 15, mask = 0x1f,
+        [1] = "slli.wDJU",
+        [9] = "srli.wDJU",
+        [17] = "srai.wDJU",
+        [25] = "rotri.wDJU",
+      },
+      [1] = {
+        shift = 16, mask = 0xf,
+        [1] = "slli.dDJV",
+        [5] = "srli.dDJV",
+        [9] = "srai.dDJV",
+        [13] = "rotri.dDJV",
+      },
+    },
+    [1] = {
+      shift = 15, mask = 0x1,
+      [0] = "bstrins.wDJMU",
+      [1] = "bstrpick.wDJMU",
+    },
+  },
   [2] = "bstrins.dDJNV",
   [3] = "bstrpick.dDJNV",
-  [4] = map_farith,
-  [8] = "sltiDJX",
-  [9] = "sltuiDJX",
-  [10] = "addi.wDJX",
-  [11] = "addi.dDJX",
-  [12] = "lu52i.dDJX",
-  [13] = "andiDJT",
-  [14] = "oriDJT",
-  [15] = "xoriDJT",
-}
-
-local map_long_i_5 = { -- Long immediate fixed-point arithmetic.
-  shift = 25, mask = 1,
-  [0] = "lu12i.wDZ",
-  [1] = "lu32i.dDZ",
 }
 
-local map_long_i_6 = {
-  shift = 25, mask = 1,
-  [0] = "pcaddiDZ",
-  [1] = "pcalau12iDZ",
-}
-
-local map_long_i_7 = {
-  shift = 25, mask = 1,
-  [0] = "pcaddu12iDZ",
-  [1] = "pcaddu18iDZ",
-}
-
-local map_ldst0_14 = {
-  shift = 15, mask = 2047,
-  [0] = "ldx.bDJK", [8] = "ldx.hDJK", [16] = "ldx.wDJK",
-  [24] = "ldx.dDJK", [32] = "stx.bDJK", [40] = "stx.hDJK",
-  [48] = "stx.wDJK", [56] = "stx.dDJK", [64] = "ldx.buDJK",
-  [72] = "ldx.huDJK", [80] = "ldx.wuDJK", [96] = "fldx.sFJK",
-  [104] = "fldx.dFJK", [112] = "fstx.sFJK", [120] = "fstx.dFJK",
-  [232] = "fldgt.sFJK", [233] = "fldgt.dFJK", [234] = "fldle.sFJK",
-  [235] = "fldle.dFJK", [236] = "fstgt.sFJK", [237] = "fstgt.dFJK",
-  [238] = "fstle.sFJK", [239] = "fstle.dFJK", [240] = "ldgt.bDJK",
-  [241] = "ldgt.hDJK", [242] = "ldgt.wDJK", [243] = "ldgt.dDJK",
-  [244] = "ldle.bDJK", [245] = "ldle.hDJK", [246] = "ldle.wDJK",
-  [247] = "ldle.dDJK", [248] = "stgt.bDJK", [249] = "stgt.hDJK",
-  [250] = "stgt.wDJK", [251] = "stgt.dDJK", [252] = "stle.bDJK",
-  [253] = "stle.hDJK", [254] = "stle.wDJK", [255] = "stle.dDJK",
-}
-
-local map_ldst1_8 = {
-  shift = 24, mask = 3,
-  [0] = "ll.wDJW",
-  [1] = "sc.wDJW",
-  [2] = "ll.dDJW",
-  [3] = "sc.dDJW",
-}
-
-local map_ldst1_9 = {
-  shift = 24, mask = 3,
-  [0] = "ldptr.wDJW",
-  [1] = "stptr.wDJW",
-  [2] = "ldptr.dDJW",
-  [3] = "stptr.dDJW",
-}
 
-local map_ldst1_10 = {
-  shift = 22, mask = 15,
-  [0] = "ld.bDJX",
-  [1] = "ld.hDJX",
-  [2] = "ld.wDJX",
-  [3] = "ld.dDJX",
-  [4] = "st.bDJX",
-  [5] = "st.hDJX",
-  [6] = "st.wDJX",
-  [7] = "st.dDJX",
-  [8] = "ld.buDJX",
-  [9] = "ld.huDJX",
-  [10] = "ld.wuDJX",
-  [12] = "fld.sFJX",
-  [13] = "fst.sFJX",
-  [14] = "fld.dFJX",
-  [15] = "fst.dFJX",
+local map_zero_31_25 = { -- [31:25] = 0
+  shift = 24, mask = 0x1,
+  [0] = map_zero_31_23,
+  [1] = {
+    shift = 18, mask = 0x3f,
+    [0] = {
+      shift = 15, mask = 0x7,
+      [1] = "fadd.sFGH",
+      [2] = "fadd.dFGH",
+      [5] = "fsub.sFGH",
+      [6] = "fsub.dFGH",
+    },
+    [1] = {
+      shift = 15, mask = 0x7,
+      [1] = "fmul.sFGH",
+      [2] = "fmul.dFGH",
+      [5] = "fdiv.sFGH",
+      [6] = "fdiv.dFGH",
+    },
+    [2] = {
+      shift = 15, mask = 0x7,
+      [1] = "fmax.sFGH",
+      [2] = "fmax.dFGH",
+      [5] = "fmin.sFGH",
+      [6] = "fmin.dFGH",
+    },
+    [3] = {
+      shift = 15, mask = 0x7,
+      [1] = "fmaxa.sFGH",
+      [2] = "fmaxa.dFGH",
+      [5] = "fmina.sFGH",
+      [6] = "fmina.dFGH",
+    },
+    [4] = {
+      shift = 15, mask = 0x7,
+      [1] = "fscaleb.sFGH",
+      [2] = "fscaleb.dFGH",
+      [5] = "fcopysign.sFGH",
+      [6] = "fcopysign.dFGH",
+    },
+    [5] = {
+      shift = 10, mask = 0xff,
+      [1] = "fabs.sFG",
+      [2] = "fabs.dFG",
+      [5] = "fneg.sFG",
+      [6] = "fneg.dFG",
+      [9] = "flogb.sFG",
+      [10] = "flogb.dFG",
+      [13] = "fclass.sFG",
+      [14] = "fclass.dFG",
+      [17] = "fsqrt.sFG",
+      [18] = "fsqrt.dFG",
+      [21] = "frecip.sFG",
+      [22] = "frecip.dFG",
+      [25] = "frsqrt.sFG",
+      [26] = "frsqrt.dFG",
+      [29] = "frecipe.sFG",
+      [30] = "frecipe.dFG",
+      [33] = "frsqrte.sFG",
+      [34] = "frsqrte.dFG",
+
+      [37] = "fmov.sFG",
+      [38] = "fmov.dFG",
+      [41] = "movgr2fr.wFJ",
+      [42] = "movgr2fr.dFJ",
+      [43] = "movgr2frh.wFJ",
+      [45] = "movfr2gr.sDG",
+      [46] = "movfr2gr.dDG",
+      [47] = "movfrh2gr.sDG",
+      [48] = "movgr2fcsrSJ",
+      [50] = "movfcsr2grDR",
+      [52] = { shift = 3, mask = 0x3, [0] = "movfr2cfEG", },
+      [53] = { shift = 8, mask = 0x3, [0] = "movcf2frFA", },
+      [54] = { shift = 3, mask = 0x3, [0] = "movgr2cfEJ", },
+      [55] = { shift = 8, mask = 0x3, [0] = "movcf2grDA", },
+    },
+    [6] = {
+      shift = 10, mask = 0xff,
+      [70] = "fcvt.s.dFG",
+      [73] = "fcvt.d.sFG",
+      [129] = "ftintrm.w.sFG",
+      [130] = "ftintrm.w.dFG",
+      [137] = "ftintrm.l.sFG",
+      [138] = "ftintrm.l.dFG",
+      [145] = "ftintrp.w.sFG",
+      [146] = "ftintrp.w.dFG",
+      [153] = "ftintrp.l.sFG",
+      [154] = "ftintrp.l.dFG",
+      [161] = "ftintrz.w.sFG",
+      [162] = "ftintrz.w.dFG",
+      [169] = "ftintrz.l.sFG",
+      [170] = "ftintrz.l.dFG",
+      [177] = "ftintrne.w.sFG",
+      [178] = "ftintrne.w.dFG",
+      [185] = "ftintrne.l.sFG",
+      [186] = "ftintrne.l.dFG",
+      [193] = "ftint.w.sFG",
+      [194] = "ftint.w.dFG",
+      [201] = "ftint.l.sFG",
+      [202] = "ftint.l.dFG",
+    },
+    [7] = {
+      shift = 10, mask = 0xff,
+      [68] = "ffint.s.wFG",
+      [70] = "ffint.s.lFG",
+      [72] = "ffint.d.wFG",
+      [74] = "ffint.d.lFG",
+      [145] = "frint.sFG",
+      [148] = "frint.dFG",
+    },
+  },
 }
 
-local map_fcmp0 = {
-  shift = 15, mask = 31,
-  [0] = "fcmp.caf.sEGH",
-  [1] = "fcmp.saf.sEGH",
-  [2] = "fcmp.clt.sEGH",
-  [3] = "fcmp.slt.sEGH",
-  [4] = "fcmp.ceq.sEGH",
-  [5] = "fcmp.seq.sEGH",
-  [6] = "fcmp.cle.sEGH",
-  [7] = "fcmp.sle.sEGH",
-  [8] = "fcmp.cun.sEGH",
-  [9] = "fcmp.sun.sEGH",
-  [10] = "fcmp.cult.sEGH",
-  [11] ="fcmp.sult.sEGH",
-  [12] = "fcmp.cueq.sEGH",
-  [13] = "fcmp.sueq.sEGH",
-  [14] = "fcmp.cule.sEGH",
-  [15] = "fcmp.sule.sEGH",
-  [16] = "fcmp.cne.sEGH",
-  [17] = "fcmp.sne.sEGH",
-  [20] = "fcmp.cor.sEGH",
-  [21] = "fcmp.sor.sEGH",
-  [24] = "fcmp.cune.sEGH",
-  [25] = "fcmp.sune.sEGH",
+local map_zero_31_26 = { -- [31:26] = 0
+  shift = 25, mask = 0x1,
+  [0] = map_zero_31_25,
+  [1] = {
+    shift = 22, mask = 0x7,
+    [0] = "sltiDJX",
+    [1] = "sltuiDJX",
+    [2] = "addi.wDJX",
+    [3] = "addi.dDJX",
+    [4] = "lu52i.dDJX",
+    [5] = "andiDJT",
+    [6] = "oriDJT",
+    [7] = "xoriDJT",
+  },
 }
 
-local map_fcmp1 = {
-  shift = 15, mask = 31,
-  [0] = "fcmp.caf.dEGH",
-  [1] = "fcmp.saf.dEGH",
-  [2] = "fcmp.clt.dEGH",
-  [3] = "fcmp.slt.dEGH",
-  [4] = "fcmp.ceq.dEGH",
-  [5] = "fcmp.seq.dEGH",
-  [6] = "fcmp.cle.dEGH",
-  [7] = "fcmp.sle.dEGH",
-  [8] = "fcmp.cun.dEGH",
-  [9] = "fcmp.sun.dEGH",
-  [10] = "fcmp.cult.dEGH",
-  [11] = "fcmp.sult.dEGH",
-  [12] = "fcmp.cueq.dEGH",
-  [13] = "fcmp.sueq.dEGH",
-  [14] = "fcmp.cule.dEGH",
-  [15] = "fcmp.sule.dEGH",
-  [16] = "fcmp.cne.dEGH",
-  [17] = "fcmp.sne.dEGH",
-  [20] = "fcmp.cor.dEGH",
-  [21] = "fcmp.sor.dEGH",
-  [24] = "fcmp.cune.dEGH",
-  [25] = "fcmp.sune.dEGH",
+local map_zero_31_28 = { -- [31:28] = 0
+  shift = 26, mask = 0x3,
+  [0] = map_zero_31_26,
+  [2] = {
+    shift = 20, mask = 0x3f,
+    [1] = "fmadd.sFGHi",
+    [2] = "fmadd.dFGHi",
+    [5] = "fmsub.sFGHi",
+    [6] = "fmsub.dFGHi",
+    [9] = "fnmadd.sFGHi",
+    [10] = "fnmadd.dFGHi",
+    [13] = "fnmsub.sFGHi",
+    [14] = "fnmsub.dFGHi",
+  },
+  [3] = {
+    shift = 20, mask = 0x7,
+    [1] = {
+      shift = 15, mask = 0x1f,
+      [0] = "fcmp.caf.EGH",
+      [1] = "fcmp.saf.EGH",
+      [2] = "fcmp.clt.EGH",
+      [3] = "fcmp.slt.EGH",
+      [4] = "fcmp.ceq.EGH",
+      [5] = "fcmp.seq.EGH",
+      [6] = "fcmp.cle.EGH",
+      [7] = "fcmp.sle.EGH",
+      [8] = "fcmp.cun.EGH",
+      [9] = "fcmp.sun.EGH",
+      [10] = "fcmp.cult.EGH",
+      [11] = "fcmp.sult.EGH",
+      [12] = "fcmp.cueq.EGH",
+      [13] = "fcmp.sueq.EGH",
+      [14] = "fcmp.cule.EGH",
+      [15] = "fcmp.sule.EGH",
+      [16] = "fcmp.cne.EGH",
+      [17] = "fcmp.sne.EGH",
+      [20] = "fcmp.cor.EGH",
+      [21] = "fcmp.sor.EGH",
+      [24] = "fcmp.cune.EGH",
+      [25] = "fcmp.sune.EGH",
+    },
+    [2] = {
+      shift = 15, mask = 0x1f,
+      [0] = "fcmp.caf.EGH",
+      [1] = "fcmp.saf.EGH",
+      [2] = "fcmp.clt.EGH",
+      [3] = "fcmp.slt.EGH",
+      [4] = "fcmp.ceq.EGH",
+      [5] = "fcmp.seq.EGH",
+      [6] = "fcmp.cle.EGH",
+      [7] = "fcmp.sle.EGH",
+      [8] = "fcmp.cun.EGH",
+      [9] = "fcmp.sun.EGH",
+      [10] = "fcmp.cult.EGH",
+      [11] = "fcmp.sult.EGH",
+      [12] = "fcmp.cueq.EGH",
+      [13] = "fcmp.sueq.EGH",
+      [14] = "fcmp.cule.EGH",
+      [15] = "fcmp.sule.EGH",
+      [16] = "fcmp.cne.EGH",
+      [17] = "fcmp.sne.EGH",
+      [20] = "fcmp.cor.EGH",
+      [21] = "fcmp.sor.EGH",
+      [24] = "fcmp.cune.EGH",
+      [25] = "fcmp.sune.EGH",
+    },
+    [16] = {
+      shift = 18, mask = 0x3,
+      [0] = "fselFGHI",
+    },
+  },
 }
 
-local map_fcmp = {
-  shift = 20, mask = 63,
-  [1] = { shift = 3, mask = 3, [0] = map_fcmp0, },
-  [2] = { shift = 3, mask = 3, [0] = map_fcmp1, },
-  [16] = { shift = 18, mask = 3, [0] = "fselFGHI", },
+local map_zero_31_29 = { -- [31:29] = 0
+  shift = 28, mask = 0x1,
+  [0] = map_zero_31_28,
+  [1] = {
+    shift = 26, mask = 0x3,
+    [0] = "addu16i.dDJY",
+    [1] = {
+      shift = 25, mask = 0x1,
+      [0] = "lu12i.wDZ",
+      [1] = "lu32i.dDZ",
+    },
+    [2] = {
+      shift = 25, mask = 0x1,
+      [0] = "pcaddiDZ",
+      [1] = "pcalau12iDZ",
+    },
+    [3] = {
+      shift = 25, mask = 0x1,
+      [0] = "pcaddu12iDZ",
+      [1] = "pcaddu18iDZ",
+    },
+  },
 }
 
-local map_fp = {
-  shift = 20, mask = 15,
-  [1] = "fmadd.sFGHi",
-  [2] = "fmadd.dFGHi",
-  [4] = "fmsub.sFGHi",
-  [5] = "fmsub.dFGHi",
-  [10] = "fnmadd.dFGHi",
-  [14] = "fnmsub.dFGHi",
+local map_zero_31_31 = { -- [31:31] = 0
+  shift = 29, mask = 0x3,
+  [0] = map_zero_31_29,
+  [1] = {
+    shift = 27, mask = 0x3,
+    [0] = {
+      shift = 24, mask = 0x7,
+      [0] = "ll.wDJW",
+      [1] = "sc.wDJW",
+      [2] = "ll.dDJW",
+      [3] = "sc.dDJW",
+      [4] = "ldptr.wDJW",
+      [5] = "stptr.wDJW",
+      [6] = "ldptr.dDJW",
+      [7] = "stptr.dDJW",
+    },
+    [1] = {
+      shift = 22, mask = 0x1f,
+      [0] = "ld.bDJX",
+      [1] = "ld.hDJX",
+      [2] = "ld.wDJX",
+      [3] = "ld.dDJX",
+      [4] = "st.bDJX",
+      [5] = "st.hDJX",
+      [6] = "st.wDJX",
+      [7] = "st.dDJX",
+      [8] = "ld.buDJX",
+      [9] = "ld.huDJX",
+      [10] = "ld.wuDJX",
+      [12] = "fld.sFJX",
+      [13] = "fst.sFJX",
+      [14] = "fld.dFJX",
+      [15] = "fst.dFJX",
+    },
+    [3] = {
+      shift = 21, mask = 0x3f,
+      [0] = {
+        shift = 15, mask = 0x3f,
+        [0] = "ldx.bDJK",
+        [8] = "ldx.hDJK",
+        [16] = "ldx.wDJK",
+        [24] = "ldx.dDJK",
+        [32] = "stx.bDJK",
+        [40] = "stx.hDJK",
+        [48] = "stx.wDJK",
+        [56] = "stx.dDJK",
+      },
+      [1] = {
+        shift = 15, mask = 0x3f,
+        [0] = "ldx.buDJK",
+        [8] = "ldx.huDJK",
+        [16] = "ldx.wuDJK",
+        [32] = "fldx.sFJK",
+        [40] = "fldx.dFJK",
+        [48] = "fstx.sFJK",
+        [56] = "fstx.dFJK",
+      },
+      [2] = {
+        shift = 15, mask = 0x3f,
+        [46] = "sc.wDJW",
+      },
+      [3] = {
+        shift = 15, mask = 0x3f,
+        [40] = "fldgt.sFJK",
+        [41] = "fldgt.dFJK",
+        [42] = "fldle.sFJK",
+        [43] = "fldle.dFJK",
+        [44] = "fstgt.sFJK",
+        [45] = "fstgt.dFJK",
+        [46] = "fstle.sFJK",
+        [47] = "fstle.dFJK",
+        [48] = "ldgt.bDJK",
+        [49] = "ldgt.hDJK",
+        [50] = "ldgt.wDJK",
+        [51] = "ldgt.dDJK",
+        [52] = "ldle.bDJK",
+        [53] = "ldle.hDJK",
+        [54] = "ldle.wDJK",
+        [55] = "ldle.dDJK",
+        [56] = "stgt.bDJK",
+        [57] = "stgt.hDJK",
+        [58] = "stgt.wDJK",
+        [59] = "stgt.dDJK",
+        [60] = "stle.bDJK",
+        [61] = "stle.hDJK",
+        [62] = "stle.wDJK",
+        [63] = "stle.dDJK",
+      },
+    },
+  },
+  [2] = {
+    shift = 26, mask = 0x7,
+    [0] = "beqzJL",
+    [1] = "bnezJL",
+    [2] = { shift = 8, mask = 3, [0] = "bceqzAL", "bcnezAL", },
+    [3] = "jirlDJO",
+    [4] = "bP",
+    [5] = "blP",
+    [6] = "beqJDO",
+    [7] = "bneJDO",
+  },
+  [3] = {
+    shift = 26, mask = 0x7,
+    [0] = "bltJDO",
+    [1] = "bgeJDO",
+    [2] = "bltuJDO",
+    [3] = "bgeuJDO",
+  },
 }
 
-local map_init = {
-  shift = 26, mask = 63,
-  [0] = map_26_0,
-  [2] = map_fp,
-  [3] = map_fcmp,
-  [4] = "addu16i.dDJY",
-  [5] = map_long_i_5,
-  [6] = map_long_i_6,
-  [7] = map_long_i_7,
-  [8] = map_ldst1_8,
-  [9] = map_ldst1_9,
-  [10] = map_ldst1_10,
-  [14] = map_ldst0_14,
-  [16] = "beqzJL",
-  [17] = "bnezJL",
-  [18] = { shift = 8, mask = 3, [0] = "bceqzAL", "bcnezAL", },
-  [19] = "jirlDJa",
-  [20] = "bP",
-  [21] = "blP",
-  [22] = "beqJDO",
-  [23] = "bneJDO",
-  [24] = "bltJDO",
-  [25] = "bgeJDO",
-  [26] = "bltuJDO",
-  [27] = "bgeuJDO",
-}
+local map_init = map_zero_31_31
 
 ------------------------------------------------------------------------------
 
@@ -474,6 +494,12 @@ local map_gpr = {
   "r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31",
 }
 
+local map_fpr = {
+  [0] = "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7",
+  "f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15",
+  "f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23",
+  "f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31",
+}
 ------------------------------------------------------------------------------
 
 -- Output a nicely formatted line with an opcode and operands.
@@ -505,148 +531,128 @@ local function get_le(ctx)
   return bor(lshift(b3, 24), lshift(b2, 16), lshift(b1, 8), b0)
 end
 
--- Decode imm.
-local function decode_si_imm(imm, bits, scale, signed, mask)
-  local n = tonumber(imm)
-  if n then
-    local m = arshift(n, scale)
-    if lshift(m, scale) == n then
-      if signed then
-        local s = arshift(band(m, mask), bits-1)
-        if s == 0 then
-          return m
-        elseif s == 1 then
-          return -(band(bnot(m), mask)+1)
-        end
-      else
-        if arshift(m, bits) == 0 then
-          return m
-        end
-      end
-    end
+-- Decode a signed immediate value
+local function decode_simm(ctx, op, shift, bits, hex_digits)
+  local mask = lshift(1, bits) - 1
+  local val = band(rshift(op, shift), mask)
+  if band(val, lshift(1, bits-1)) ~= 0 then
+    val = val - lshift(1, bits)
+  end
+  ctx.rel = val
+  if hex_digits then
+    local fmt = "%d(0x%0"..hex_digits.."x)"
+    return format(fmt, val, band(val, mask))
+  else
+    return format("%d(0x%x)", val, band(val, mask))
   end
 end
 
+-- Similar for unsigned immediate (no sign extension)
+local function decode_uimm(ctx, op, shift, bits, hex_digits)
+  local mask = lshift(1, bits) - 1
+  local val = band(rshift(op, shift), mask)
+  ctx.rel = val
+  if hex_digits then
+    local fmt = "%d(0x%0"..hex_digits.."x)"
+    return format(fmt, val, val)
+  else
+    return format("%d(0x%x)", val, val)
+  end
+end
+
+-- Decode a PC-relative branch offset
+local function decode_offs(ctx, offs, bits)
+  local mask = lshift(1, bits) - 1
+  if band(offs, lshift(1, bits-1)) ~= 0 then
+    offs = offs - lshift(1, bits)
+  end
+  -- branch offsets are in units of 4 bytes (<< 2)
+  local target = ctx.addr + ctx.pos + lshift(offs, 2)
+  ctx.rel = target
+  return format("0x%08x", target)
+end
+
 -- Disassemble a single instruction.
 local function disass_ins(ctx)
   local op = ctx:get()
   local operands = {}
-  local last = nil
   ctx.op = op
   ctx.rel = nil
 
-  local opat = ctx.map_pri[rshift(op, 26)]
+  local opat = ctx.map_pri[band(rshift(op, ctx.map_pri.shift), ctx.map_pri.mask)]
   while type(opat) ~= "string" do
     if not opat then return unknown(ctx) end
     opat = opat[band(rshift(op, opat.shift), opat.mask)]
   end
-  local name, pat = match(opat, "^([a-z0-9_.]*)(.*)")
-  local altname, pat2 = match(pat, "|([a-z0-9_.|]*)(.*)")
-  if altname then pat = pat2 end
 
+  local name, pat = match(opat, "^([a-z0-9.]*)(.*)")
   for p in gmatch(pat, ".") do
     local x = nil
-    if p == "D" then
-      x = map_gpr[band(rshift(op, 0), 31)]
-    elseif p == "J" then
-      x = map_gpr[band(rshift(op, 5), 31)]
-    elseif p == "K" then
-      x = map_gpr[band(rshift(op, 10), 31)]
-    elseif p == "F" then
-      x = "f"..band(rshift(op, 0), 31)
-    elseif p == "G" then
-      x = "f"..band(rshift(op, 5), 31)
-    elseif p == "H" then
-      x = "f"..band(rshift(op, 10), 31)
-    elseif p == "i" then
-      x = "f"..band(rshift(op, 15), 31)
-    elseif p == "S" then
-      x = "fcsr"..band(rshift(op, 0), 31)
-    elseif p == "R" then
-      x = "fcsr"..band(rshift(op, 5), 31)
-    elseif p == "E" then
-      x = "fcc"..band(rshift(op, 0), 7)
-    elseif p == "A" then
-      x = "fcc"..band(rshift(op, 5), 7)
-    elseif p == "I" then
-      x = "fcc"..band(rshift(op, 15), 7)
+    if p == "D" then -- rd
+      x = map_gpr[band(op, 0x1f)]
+    elseif p == "J" then -- rj
+      x = map_gpr[band(rshift(op, 5), 0x1f)]
+    elseif p == "K" then -- rk
+      x = map_gpr[band(rshift(op, 10), 0x1f)]
+    elseif p == "F" then -- fd
+      x = map_fpr[band(op, 0x1f)]
+    elseif p == "G" then -- fj
+      x = map_fpr[band(rshift(op, 5), 0x1f)]
+    elseif p == "H" then -- fk
+      x = map_fpr[band(rshift(op, 10), 0x1f)]
+    elseif p == "i" then  -- fa
+      x = map_fpr[band(rshift(op, 15), 0x1f)]
+    elseif p == "S" then  -- fcsr
+      x = "fcsr"..band(op, 0x1f)
+    elseif p == "R" then  -- fcsr
+      x = "fcsr"..band(rshift(op, 5), 0x1f)
+    elseif p == "E" then  -- cd
+      x = "fcc"..band(op, 0x7)
+    elseif p == "A" then  -- cj
+      x = "fcc"..band(rshift(op, 5), 0x7)
+    elseif p == "I" then  -- ca
+      x = "fcc"..band(rshift(op, 15), 0x7)
     elseif p == "Q" then -- sa2
-      x = band(rshift(op, 15), 3)
-      ctx.rel = x
-      x = format("%d", x)
+      x = decode_uimm(ctx, op, 15, 2, nil)
     elseif p == "B" then -- sa3
-      x = band(rshift(op, 15), 7)
-      ctx.rel = x
-      x = format("%d", x)
+      x = decode_uimm(ctx, op, 15, 3, nil)
     elseif p == "M" then -- msbw
-      x = band(rshift(op, 16), 31)
-      ctx.rel = x
-      x = format("%d(0x%x)", x, x)
+      x = decode_uimm(ctx, op, 16, 5, 2)
     elseif p == "N" then -- msbd
-      x = band(rshift(op, 16), 63)
-      ctx.rel = x
-      x = format("%d(0x%x)", x, x)
+      x = decode_uimm(ctx, op, 16, 6, 2)
     elseif p == "U" then -- ui5
-      x = band(rshift(op, 10), 31)
-      ctx.rel = x
-      x = format("%d(0x%x)", x, x)
+      x = decode_uimm(ctx, op, 10, 5, 2)
     elseif p == "V" then -- ui6
-      x = band(rshift(op, 10), 63)
-      ctx.rel = x
-      x = format("%d(0x%x)", x, x)
+      x = decode_uimm(ctx, op, 10, 6, 2)
     elseif p == "T" then -- ui12
-      x = band(rshift(op, 10), 4095)
-      ctx.rel = x
-      x = format("%d(0x%x)", x, x)
+      x = decode_uimm(ctx, op, 10, 12, 3)
     elseif p == "W" then -- si14
-      x = band(rshift(op, 10), 16383)
-      x = decode_si_imm(x, 14, 0, true, 0x3fff)
-      ctx.rel = x
-      x = format("%d(0x%04x)", x, band(x, 0x3fff))
+      x = decode_simm(ctx, op, 10, 14, 4)
     elseif p == "X" then -- si12
-      x = band(rshift(op, 10), 4095)
-      x = decode_si_imm(x, 12, 0, true, 0xfff)
-      ctx.rel = x
-      x = format("%d(0x%03x)", x, band(x, 0xfff))
-    elseif p == "o" then
-      local disp = band((rshift(op, 10)), 0xfff)
-      operands[#operands] = format("%s, %d", last, disp)
+      x = decode_simm(ctx, op, 10, 12, 3)
     elseif p == "Y" then -- si16
-      x = band(rshift(op, 10), 65535)
-      x = decode_si_imm(x, 16, 0, true, 0xffff)
-      ctx.rel = x
-      x = format("%d(0x%04x)", x, band(x, 0xffff))
+      x = decode_simm(ctx, op, 10, 16, 4)
     elseif p == "Z" then -- si20
-      x = band(rshift(op, 10), 1048575)
-      x = decode_si_imm(x, 20, 0, true, 0xfffff)
-      ctx.rel = x
-      x = format("%d(0x%05x)", x, band(x, 0xfffff))
+      x = decode_simm(ctx, op, 5, 20, 5)
     elseif p == "C" then -- code
-      x = band(rshift(op, 0), 32767)
+      x = band(op, 0x1f)
     elseif p == "O" then -- offs[15:0]
-      x = band(rshift(op, 10), 65535)
-      x = decode_si_imm(x, 16, 0, true, 0xffff)
-      ctx.rel = x
-      x = format("%d(0x%04x)", x, band(x, 0xffff))
+      if name == "jirl" then
+        x = decode_simm(ctx, op, 10, 16, 4)
+      else
+        local offs = band(rshift(op, 10), 0xffff)
+        x = decode_offs(ctx, offs, 16)
+      end
     elseif p == "L" then -- offs[15:0] + offs[20:16]
-      x = lshift(band(op, 31), 16) + band(rshift(op, 10), 65535)
-      x = decode_si_imm(x, 21, 0, true, 0x1fffff)
-      ctx.rel = x
-      x = format("%d(0x%06x)", x, band(x, 0x1fffff))
+      local offs = lshift(band(op, 0x1f), 16) + band(rshift(op, 10), 0xffff)
+      x = decode_offs(ctx, offs, 21)
     elseif p == "P" then -- offs[15:0] + offs[25:16]
-      x = lshift(band(op, 1023), 16) + band(rshift(op, 10), 65535)
-      x = decode_si_imm(x, 26, 0, true, 0x3ffffff)
-      ctx.rel = x
-      x = format("%d(0x%07x)", x, band(x, 0x3ffffff))
-    elseif p == "a" then
-      x = band(rshift(op, 10), 65535)
-      x = decode_si_imm(x, 16, 0, true, 0xffff)
-      ctx.rel = x
-      x = format("%d(0x%04x)", x, band(x, 0xffff))
+      local offs = lshift(band(op, 0x3ff), 16) + band(rshift(op, 10), 0xffff)
+      x = decode_offs(ctx, offs, 26)
     else
       assert(false)
     end
-    if x then operands[#operands+1] = x; last = x end
+    if x then operands[#operands+1] = x end
   end
 
   return putop(ctx, name, operands)
@@ -686,7 +692,7 @@ end
 -- Return register name for RID.
 local function regname(r)
   if r < 32 then return map_gpr[r] end
-  return "f"..(r-32)
+  return map_fpr[r-32]
 end
 
 -- Public module functions.