Almost done with all codegen for Chapter 12, except not all unsigned int works...

Author: dplassgit

examples/arithmetic_ops.c

@@ -0,0 +1,29 @@
+/* Test basic arithmetic operations on unsigned integers
+ * None of these operations wrap around; that's tested separately in arithmetic_wraparound
+ */
+
+unsigned int ui_a;
+unsigned int ui_b;
+
+int division(void) {
+    // ui_a = 100
+    // ui_b = 4294967294
+
+    /* ui_a/ui_b is 0.
+     * If you interpreted these as signed values, ui_b would be -2
+     * and ui_a / ui_b would be -50
+     */
+    return (ui_a / ui_b == 0);
+}
+
+int main(void) {
+
+    ui_a = 100u;
+    ui_b = 4294967294u;
+
+    if (!division()) {
+        return 4;
+    }
+
+    return 0;
+}

src/com/plasstech/lang/c/codegen/AsmNode.java

@@ -35,6 +35,10 @@ interface Visitor<R> {
     R visit(Call op);
 
     R visit(Movsx op);
+
+    R visit(MovZeroExtend op);
+
+    R visit(Div op);
   }
 
   <R> R accept(Visitor<R> visitor);

src/com/plasstech/lang/c/codegen/AssemblyType.java

@@ -16,6 +16,7 @@ public enum AssemblyType {
   }
 
   public static AssemblyType from(Type type) {
+    // page 289
     if (type.equals(Type.LONG) || type.equals(Type.UNSIGNED_LONG)) {
       return Quadword;
     } else if (type.equals(Type.INT) || type.equals(Type.UNSIGNED_INT)) {

src/com/plasstech/lang/c/codegen/CodeEmission.java

@@ -77,6 +77,9 @@ public Void visit(AsmStaticVariable n) {
     }
     emit(".align %d", n.alignment());
     emit0("%s:", n.name());
+
+    // These seem to be independent of signed-ness
+    // Page 291
     if (n.init().valueAsLong() == 0) {
       emit(".zero %d", n.init().bytes());
     } else {
@@ -160,4 +163,14 @@ public Void visit(Call n) {
   public Void visit(Movsx n) {
     return emit(n);
   }
+
+  @Override
+  public Void visit(MovZeroExtend op) {
+    throw new UnsupportedOperationException("movzeroextend");
+  }
+
+  @Override
+  public Void visit(Div op) {
+    return emit(op);
+  }
 }

src/com/plasstech/lang/c/codegen/CondCode.java

@@ -12,7 +12,12 @@ public enum CondCode {
   G,
   GE,
   L,
-  LE;
+  LE,
+  // Page 287
+  A,
+  AE,
+  B,
+  BE;
 
   private static final Map<TokenType, CondCode> FROM_TOKEN_TYPE = ImmutableMap.of(
       TokenType.EQEQ, E,
@@ -22,7 +27,20 @@ public enum CondCode {
       TokenType.LT, L,
       TokenType.LEQ, LE);
 
-  public static CondCode from(TokenType operator) {
-    return FROM_TOKEN_TYPE.get(operator);
+  // Page 289
+  private static final Map<TokenType, CondCode> FROM_TOKEN_TYPE_UNSIGNED = ImmutableMap.of(
+      TokenType.EQEQ, E,
+      TokenType.NEQ, NE,
+      TokenType.GT, A,
+      TokenType.GEQ, AE,
+      TokenType.LT, B,
+      TokenType.LEQ, BE);
+
+  public static CondCode from(TokenType operator, boolean signed) {
+    if (signed) {
+      return FROM_TOKEN_TYPE.get(operator);
+    } else {
+      return FROM_TOKEN_TYPE_UNSIGNED.get(operator);
+    }
   }
 }

src/com/plasstech/lang/c/codegen/Div.java

@@ -0,0 +1,14 @@
+package com.plasstech.lang.c.codegen;
+
+/** eax=eax/operand for unsigned */
+public record Div(AssemblyType type, Operand operand) implements Instruction {
+  @Override
+  public <R> R accept(Visitor<R> visitor) {
+    return visitor.visit(this);
+  }
+
+  @Override
+  public final String toString() {
+    return String.format("div%s %s", type().suffix(), operand().toString(type()));
+  }
+}

src/com/plasstech/lang/c/codegen/MovZeroExtend.java

@@ -0,0 +1,9 @@
+package com.plasstech.lang.c.codegen;
+
+/** Page 287 */
+public record MovZeroExtend(Operand src, Operand dst) implements Instruction {
+  @Override
+  public <R> R accept(Visitor<R> visitor) {
+    return visitor.visit(this);
+  }
+}

src/com/plasstech/lang/c/codegen/tacky/FixupVisitor.java

@@ -16,13 +16,15 @@
 import com.plasstech.lang.c.codegen.Call;
 import com.plasstech.lang.c.codegen.Cdq;
 import com.plasstech.lang.c.codegen.Cmp;
+import com.plasstech.lang.c.codegen.Div;
 import com.plasstech.lang.c.codegen.Idiv;
 import com.plasstech.lang.c.codegen.Imm;
 import com.plasstech.lang.c.codegen.Instruction;
 import com.plasstech.lang.c.codegen.Jmp;
 import com.plasstech.lang.c.codegen.JmpCC;
 import com.plasstech.lang.c.codegen.Label;
 import com.plasstech.lang.c.codegen.Mov;
+import com.plasstech.lang.c.codegen.MovZeroExtend;
 import com.plasstech.lang.c.codegen.Movsx;
 import com.plasstech.lang.c.codegen.Operand;
 import com.plasstech.lang.c.codegen.Push;
@@ -112,6 +114,17 @@ public List<Instruction> visit(Idiv n) {
     return ImmutableList.of(n);
   }
 
+  @Override
+  public List<Instruction> visit(Div n) {
+    // Can't divide by a constant; use r10 as an intermediary. See page 290
+    if (n.operand() instanceof Imm) {
+      return ImmutableList.of(
+          new Mov(n.type(), n.operand(), R10),
+          new Div(n.type(), R10));
+    }
+    return ImmutableList.of(n);
+  }
+
   @Override
   public List<Instruction> visit(AsmUnary n) {
     return ImmutableList.of(n);
@@ -232,4 +245,19 @@ public List<Instruction> visit(Movsx op) {
     }
     return ImmutableList.of(op);
   }
+
+  @Override
+  public List<Instruction> visit(MovZeroExtend op) {
+    // Page 290
+    if (op.dst().inMemory()) {
+      // if dest is memory, rewrite to two:
+      //  1. mov(longword, src, reg 11)
+      //  2. mov(quadword, r11, dest)
+      return ImmutableList.of(
+          new Mov(AssemblyType.Longword, op.src(), R11),
+          new Mov(AssemblyType.Quadword, R11, op.dst()));
+    }
+    // dest is a register: rewrite to mov longword src, dst
+    return ImmutableList.of(new Mov(AssemblyType.Longword, op.src(), op.dst()));
+  }
 }

src/com/plasstech/lang/c/codegen/tacky/PseudoRegisterReplacer.java

@@ -16,13 +16,15 @@
 import com.plasstech.lang.c.codegen.Cdq;
 import com.plasstech.lang.c.codegen.Cmp;
 import com.plasstech.lang.c.codegen.Data;
+import com.plasstech.lang.c.codegen.Div;
 import com.plasstech.lang.c.codegen.Idiv;
 import com.plasstech.lang.c.codegen.Imm;
 import com.plasstech.lang.c.codegen.Instruction;
 import com.plasstech.lang.c.codegen.Jmp;
 import com.plasstech.lang.c.codegen.JmpCC;
 import com.plasstech.lang.c.codegen.Label;
 import com.plasstech.lang.c.codegen.Mov;
+import com.plasstech.lang.c.codegen.MovZeroExtend;
 import com.plasstech.lang.c.codegen.Movsx;
 import com.plasstech.lang.c.codegen.ObjEntry;
 import com.plasstech.lang.c.codegen.Operand;
@@ -191,4 +193,17 @@ public Instruction visit(Movsx op) {
     Operand newDest = remap(op.dst());
     return new Movsx(newSrc, newDest);
   }
+
+  @Override
+  public Instruction visit(MovZeroExtend op) {
+    Operand newSrc = remap(op.src());
+    Operand newDest = remap(op.dst());
+    return new MovZeroExtend(newSrc, newDest);
+  }
+
+  @Override
+  public Instruction visit(Div op) {
+    Operand newOperand = remap(op.operand());
+    return new Div(op.type(), newOperand);
+  }
 }

src/com/plasstech/lang/c/codegen/tacky/TackyCodeGen.java

@@ -136,6 +136,7 @@ public TackyVal visit(Compound n) {
 
   @Override
   public <T extends Number> TackyVal visit(Constant<T> n) {
+    // this may be the error - something about subtracting 2^32?
     return new TackyConstant(n.type(), n.asLong());
   }