ack/lang/cem/cemcom/conversion.c

147 lines
2.9 KiB
C

/*
* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
* See the copyright notice in the ACK home directory, in the file "Copyright".
*/
/* $Header$ */
/* C O N V E R S I O N - C O D E G E N E R A T O R */
#include "nofloat.h"
#include <em.h>
#include "arith.h"
#include "type.h"
#include "sizes.h"
#include "Lpars.h"
#define T_SIGNED 1
#define T_UNSIGNED 2
#ifndef NOFLOAT
#define T_FLOATING 3
#endif NOFLOAT
/* conversion() generates the EM code for a conversion between
the types char, short, int, long, float, double and pointer.
In case of integral type, the notion signed / unsigned is
taken into account.
The EM code to obtain this conversion looks like:
LOC sizeof(from_type)
LOC sizeof(to_type)
C??
*/
conversion(from_type, to_type)
register struct type *from_type, *to_type;
{
register arith from_size = from_type->tp_size;
register arith to_size = to_type->tp_size;
int from_fund = fundamental(from_type);
int to_fund = fundamental(to_type);
if (to_size < word_size) to_size = word_size;
if (from_size == to_size && from_fund == to_fund)
return;
switch (from_fund) {
case T_SIGNED:
switch (to_fund) {
case T_SIGNED:
C_loc(from_size);
C_loc(to_size);
C_cii();
break;
case T_UNSIGNED:
#ifndef NOFLOAT
case T_FLOATING:
#endif NOOFLOAT
if (from_size < word_size) {
C_loc(from_size);
C_loc(word_size);
C_cii();
from_size = word_size;
}
C_loc(from_size);
C_loc(to_size);
if (to_fund == T_UNSIGNED) C_ciu();
else C_cif();
break;
}
break;
case T_UNSIGNED:
if (from_size < word_size) from_size = word_size;
C_loc(from_size);
C_loc(to_size);
switch (to_fund) {
case T_SIGNED:
C_cui();
break;
case T_UNSIGNED:
C_cuu();
break;
#ifndef NOFLOAT
case T_FLOATING:
C_cuf();
break;
#endif NOFLOAT
}
break;
#ifndef NOFLOAT
case T_FLOATING:
C_loc(from_size);
C_loc(to_size);
switch (to_fund) {
case T_SIGNED:
C_cfi();
break;
case T_UNSIGNED:
C_cfu();
break;
case T_FLOATING:
C_cff();
break;
}
break;
#endif NOFLOAT
default:
crash("(conversion) illegal type conversion");
}
if (to_type->tp_size < word_size
#ifndef NOFLOAT
&& to_fund != T_FLOATING
#endif NOFLOAT
) {
extern long full_mask[];
C_loc((arith) full_mask[(int)(to_type->tp_size)]);
C_and(word_size);
if (to_fund == T_SIGNED) {
C_loc(to_type->tp_size);
C_loc(word_size);
C_cii();
}
}
}
/* fundamental() returns in which category a given type falls:
signed, unsigned or floating
*/
int
fundamental(tp)
register struct type *tp;
{
switch (tp->tp_fund) {
case CHAR:
case SHORT:
case INT:
case ERRONEOUS:
case LONG:
case ENUM:
return tp->tp_unsigned ? T_UNSIGNED : T_SIGNED;
#ifndef NOFLOAT
case FLOAT:
case DOUBLE:
return T_FLOATING;
#endif NOFLOAT
case POINTER: /* pointer : signed / unsigned ??? */
return T_SIGNED;
}
return 0;
}