feat(decode): implement RV64I shift instructions

Author: EmbroiderSnow

sim/src/decode.c

@@ -85,13 +85,15 @@ void decode_exec(Decode *s){
     // SLTI, SLTIU
     INSTPAT("??????? ????? ????? 010 ????? 00100 11", slti   , I, R(rd) = (int64_t)src1 < (int64_t)imm);
     INSTPAT("??????? ????? ????? 011 ????? 00100 11", sltiu  , I, R(rd) = src1 < imm);
-    // SLLI, SRLI, SRAI
-    INSTPAT("0000000 ????? ????? 001 ????? 00100 11", slli   , I, R(rd) = src1 << (imm & 0x3f));
-    INSTPAT("0000000 ????? ????? 101 ????? 00100 11", srli   , I, R(rd) = src1 >> (imm & 0x3f));
-    INSTPAT("0100000 ????? ????? 101 ????? 00100 11", srai   , I, R(rd) = (int64_t)src1 >> (imm & 0x3f));
+    // SLLI, SRLI, SRAI, SLLIW, SRLIW, SRAIW
+    INSTPAT("000000? ????? ????? 001 ????? 00100 11", slli   , I, R(rd) = src1 << (imm & 0x3f));
+    INSTPAT("000000? ????? ????? 101 ????? 00100 11", srli   , I, R(rd) = src1 >> (imm & 0x3f));
+    INSTPAT("010000? ????? ????? 101 ????? 00100 11", srai   , I, R(rd) = (int64_t)src1 >> (imm & 0x3f));
+    INSTPAT("0000000 ????? ????? 001 ????? 00110 11", slliw  , I, R(rd) = SEXT((uint32_t)src1 << (imm & 0x1f), 32));
+    INSTPAT("0000000 ????? ????? 101 ????? 00110 11", srliw  , I, R(rd) = SEXT((uint32_t)src1 >> (imm & 0x1f), 32));
+    INSTPAT("0100000 ????? ????? 101 ????? 00110 11", sraiw  , I, R(rd) = SEXT((int32_t)src1 >> (imm & 0x1f), 32));
     // XORI, ORI, ANDI
     // ADDIW
-    // SLLI, SRLI, SRAI, SLLIW, SRLIW, SRAIW
     // ADD, SUB, SLL, SLT, SLTU, XOR, SRL, SRA, OR, AND
     // ADDW, SUBW, SLLW, SRLW, SRAW
     // FENCE, FENCE.I