public virtual void CGenPush(Env env, CGenState state)
{
Reg ret = CGenValue(env, state);
switch (type.kind) {
case ExprType.Kind.CHAR:
case ExprType.Kind.UCHAR:
case ExprType.Kind.SHORT:
case ExprType.Kind.USHORT:
case ExprType.Kind.LONG:
case ExprType.Kind.ULONG:
// Integral
if (ret != Reg.EAX) {
throw new InvalidProgramException("Integral values should be returned to %eax");
}
state.CGenPushLong(Reg.EAX);
break;
case ExprType.Kind.FLOAT:
// Float
if (ret != Reg.ST0) {
throw new InvalidProgramException("Floats should be returned to %st(0)");
}
state.CGenExpandStackBy4Bytes();
state.FSTS(0, Reg.ESP);
break;
case ExprType.Kind.DOUBLE:
// Double
if (ret != Reg.ST0) {
throw new InvalidProgramException("Doubles should be returned to %st(0)");
}
state.CGenExpandStackBy8Bytes();
state.FSTL(0, Reg.ESP);
break;
case ExprType.Kind.ARRAY:
case ExprType.Kind.FUNCTION:
case ExprType.Kind.POINTER:
// Pointer
if (ret != Reg.EAX) {
throw new InvalidProgramException("Pointer values should be returned to %eax");
}
state.CGenPushLong(Reg.EAX);
break;
case ExprType.Kind.INCOMPLETE_ARRAY:
case ExprType.Kind.VOID:
throw new InvalidProgramException(type.kind.ToString() + " can't be pushed onto the stack");
case ExprType.Kind.STRUCT_OR_UNION:
throw new NotImplementedException();
}
}
public override Reg CGenValue(Env env, CGenState state)
{
// 1. %eax = &lhs
lvalue.CGenAddress(env, state);
// 2. push %eax
Int32 pos = state.CGenPushLong(Reg.EAX);
Reg ret = rvalue.CGenValue(env, state);
switch (lvalue.type.kind) {
case ExprType.Kind.CHAR:
case ExprType.Kind.UCHAR:
// pop %ebx
// now %ebx = %lhs
state.CGenPopLong(pos, Reg.EBX);
// *%ebx = %al
state.MOVB(Reg.AL, 0, Reg.EBX);
return Reg.EAX;
case ExprType.Kind.SHORT:
case ExprType.Kind.USHORT:
// pop %ebx
// now %ebx = %lhs
state.CGenPopLong(pos, Reg.EBX);
// *%ebx = %al
state.MOVW(Reg.AX, 0, Reg.EBX);
return Reg.EAX;
case ExprType.Kind.LONG:
case ExprType.Kind.ULONG:
case ExprType.Kind.POINTER:
// pop %ebx
// now %ebx = &lhs
state.CGenPopLong(pos, Reg.EBX);
// *%ebx = %al
state.MOVL(Reg.EAX, 0, Reg.EBX);
return Reg.EAX;
case ExprType.Kind.FLOAT:
// pop %ebx
// now %ebx = &lhs
state.CGenPopLong(pos, Reg.EBX);
// *%ebx = %st(0)
state.FSTS(0, Reg.EBX);
return Reg.ST0;
case ExprType.Kind.DOUBLE:
// pop %ebx
// now %ebx = &lhs
state.CGenPopLong(pos, Reg.EBX);
// *%ebx = %st(0)
state.FSTL(0, Reg.EBX);
return Reg.ST0;
case ExprType.Kind.STRUCT_OR_UNION:
// pop %edi
// now %edi = &lhs
state.CGenPopLong(pos, Reg.EDI);
// %esi = &rhs
state.MOVL(Reg.EAX, Reg.ESI);
// %ecx = nbytes
state.MOVL(lvalue.type.SizeOf, Reg.ECX);
state.CGenMemCpy();
// %eax = &lhs
state.MOVL(Reg.EDI, Reg.EAX);
return Reg.EAX;
case ExprType.Kind.FUNCTION:
case ExprType.Kind.VOID:
case ExprType.Kind.ARRAY:
case ExprType.Kind.INCOMPLETE_ARRAY:
default:
throw new InvalidProgramException("cannot assign to a " + type.kind.ToString());
}
}
public override Reg CGenValue(CGenState state)
{
// 1. %eax = &left
this.Left.CGenAddress(state);
// 2. push %eax
Int32 pos = state.CGenPushLong(Reg.EAX);
Reg ret = this.Right.CGenValue(state);
switch (this.Left.Type.Kind)
{
case ExprTypeKind.CHAR:
case ExprTypeKind.UCHAR:
// pop %ebx
// now %ebx = %Left
state.CGenPopLong(pos, Reg.EBX);
// *%ebx = %al
state.MOVB(Reg.AL, 0, Reg.EBX);
return(Reg.EAX);
case ExprTypeKind.SHORT:
case ExprTypeKind.USHORT:
// pop %ebx
// now %ebx = %Left
state.CGenPopLong(pos, Reg.EBX);
// *%ebx = %al
state.MOVW(Reg.AX, 0, Reg.EBX);
return(Reg.EAX);
case ExprTypeKind.LONG:
case ExprTypeKind.ULONG:
case ExprTypeKind.POINTER:
// pop %ebx
// now %ebx = &Left
state.CGenPopLong(pos, Reg.EBX);
// *%ebx = %al
state.MOVL(Reg.EAX, 0, Reg.EBX);
return(Reg.EAX);
case ExprTypeKind.FLOAT:
// pop %ebx
// now %ebx = &Left
state.CGenPopLong(pos, Reg.EBX);
// *%ebx = %st(0)
state.FSTS(0, Reg.EBX);
return(Reg.ST0);
case ExprTypeKind.DOUBLE:
// pop %ebx
// now %ebx = &Left
state.CGenPopLong(pos, Reg.EBX);
// *%ebx = %st(0)
state.FSTL(0, Reg.EBX);
return(Reg.ST0);
case ExprTypeKind.STRUCT_OR_UNION:
// pop %edi
// now %edi = &Left
state.CGenPopLong(pos, Reg.EDI);
// %esi = &Right
state.MOVL(Reg.EAX, Reg.ESI);
// %ecx = nbytes
state.MOVL(this.Left.Type.SizeOf, Reg.ECX);
state.CGenMemCpy();
// %eax = &Left
state.MOVL(Reg.EDI, Reg.EAX);
return(Reg.EAX);
case ExprTypeKind.FUNCTION:
case ExprTypeKind.VOID:
case ExprTypeKind.ARRAY:
case ExprTypeKind.INCOMPLETE_ARRAY:
default:
throw new InvalidProgramException("cannot assign to a " + this.Type.Kind);
}
}
// Before the actual calculation, the state is set to this.
//
// regs:
// %ecx = &expr
//
// stack:
// +-------+
// | ..... | <- %esp
// +-------+
//
// float stack:
// +-------+
// | expr | <- %st(1)
// +-------+
// | 1.0 | <- %st(0)
// +-------+
//
// 1. Compute %st(1) + %st(0) and stores in %st(0).
//
// regs:
// %ecx = &expr
//
// stack:
// +-------+
// | ..... | <- %esp
// +-------+
//
// float stack:
// +------------+
// | expr | <- %st(1)
// +------------+
// | expr + 1.0 | <- %st(0)
// +------------+
//
// 2. Store %st(0) in memory.
//
// regs:
// %ecx = &expr
//
// stack:
// +-------+
// | ..... | <- %esp
// +-------+
//
// float stack:
// +------------+
// | expr + 1.0 | <- %st(0)
// +------------+
//
public override void CalcAndSaveFloat(CGenState state)
{
state.FADD(1, 0);
state.FSTS(0, Reg.ECX);
}
public override void CalcAndSaveFloat(CGenState state)
{
state.FSUB(1, 0);
state.FSTS(0, Reg.ECX);
}