beq and bne

ef8504e9 · George Hotz · bc7c1f01 · ef8504e9
Commit ef8504e9 authored Sep 30, 2021 by George Hotz
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Showing with 11 additions and 2 deletions

MIPS.sol contracts/MIPS.sol +11 -2

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--- a/contracts/MIPS.sol
+++ b/contracts/MIPS.sol
@@ -114,8 +114,17 @@ contract MIPS {
      storeAddr = REG_PC;
    }

-    // execute
-    uint32 val = execute(insn, rs, rt, mem);
+    uint32 val;
+    if (opcode == 4 || opcode == 5) {   // beq/bne
+      rt = m.ReadMemory(stateHash, REG_OFFSET + ((insn >> 14) & 0x7C));
+      if ((rs == rt && opcode == 4) || (rs != rt && opcode == 5)) {
+        val = pc + (SE(insn&0xFFFF, 16)<<2);
+        storeAddr = REG_PC;
+      }
+    } else {
+      // ALU
+      val = execute(insn, rs, rt, mem);
+    }

    // write back
    if (storeAddr != 0xFFFFFFFF) {