Fix logical-AND operation (#138)

The current implementation of logical-and is incorrect. Fix it with
the equivalent instruction combination.

The short-circuit evaluation should be done later.

Close #120

Author: vacantron

src/arm-codegen.c

@@ -80,7 +80,6 @@ void update_elf_offset(ph2_ir_t *ph2_ir)
     case OP_bit_or:
     case OP_bit_xor:
     case OP_negate:
-    case OP_log_and:
     case OP_bit_not:
         elf_offset += 4;
         return;
@@ -119,6 +118,9 @@ void update_elf_offset(ph2_ir_t *ph2_ir)
     case OP_return:
         elf_offset += 24;
         return;
+    case OP_log_and:
+        elf_offset += 28;
+        return;
     default:
         printf("Unknown opcode\n");
         abort();
@@ -439,8 +441,14 @@ void emit_ph2_ir(ph2_ir_t *ph2_ir)
         emit(__mov_i(__EQ, rd, 1));
         return;
     case OP_log_and:
-        /* FIXME: bad logical-and instruction */
-        emit(__and_r(__AL, rd, rn, rm));
+        /* TODO: short-circuit evaluation */
+        emit(__teq(rn));
+        emit(__mov_i(__NE, __r8, 1));
+        emit(__mov_i(__EQ, __r8, 0));
+        emit(__teq(rm));
+        emit(__mov_i(__NE, rd, 1));
+        emit(__mov_i(__EQ, rd, 0));
+        emit(__and_r(__AL, rd, rd, __r8));
         return;
     case OP_log_or:
         emit(__or_r(__AL, rd, rn, rm));

src/riscv-codegen.c

@@ -58,7 +58,6 @@ void update_elf_offset(ph2_ir_t *ph2_ir)
     case OP_bit_or:
     case OP_bit_xor:
     case OP_negate:
-    case OP_log_and:
     case OP_bit_not:
         elf_offset += 4;
         return;
@@ -90,6 +89,7 @@ void update_elf_offset(ph2_ir_t *ph2_ir)
     case OP_branch:
         elf_offset += 20;
         return;
+    case OP_log_and:
     case OP_return:
         elf_offset += 24;
         return;
@@ -413,8 +413,13 @@ void emit_ph2_ir(ph2_ir_t *ph2_ir)
         emit(__xori(rd, rd, 1));
         return;
     case OP_log_and:
-        /* FIXME: bad logical-and instruction */
-        emit(__and(rd, rs1, rs2));
+        /* TODO: short-circuit evaluation */
+        emit(__xor(__t0, rs1, rs2));
+        emit(__sub(rd, __t0, rs1));
+        emit(__sub(__t0, __t0, rs2));
+        emit(__sltu(rd, __zero, rd));
+        emit(__sltu(__t0, __zero, __t0));
+        emit(__and(rd, rd, __t0));
         return;
     case OP_log_or:
         emit(__or(rd, rs1, rs2));