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/*
Crown Copyright (c) 1997
This TenDRA(r) Computer Program is subject to Copyright
owned by the United Kingdom Secretary of State for Defence
acting through the Defence Evaluation and Research Agency
(DERA). It is made available to Recipients with a
royalty-free licence for its use, reproduction, transfer
to other parties and amendment for any purpose not excluding
product development provided that any such use et cetera
shall be deemed to be acceptance of the following conditions:-
(1) Its Recipients shall ensure that this Notice is
reproduced upon any copies or amended versions of it;
(2) Any amended version of it shall be clearly marked to
show both the nature of and the organisation responsible
for the relevant amendment or amendments;
(3) Its onward transfer from a recipient to another
party shall be deemed to be that party's acceptance of
these conditions;
(4) DERA gives no warranty or assurance as to its
quality or suitability for any purpose and DERA accepts
no liability whatsoever in relation to any use to which
it may be put.
*/
/**********************************************************************
$Author: release $
$Date: 1998/01/17 15:56:06 $
$Revision: 1.1.1.1 $
$Log: regalloc.c,v $
* Revision 1.1.1.1 1998/01/17 15:56:06 release
* First version to be checked into rolling release.
*
* Revision 1.2 1995/09/22 15:49:18 currie
* added outpar
*
* Revision 1.1 1995/04/13 09:08:06 currie
* Initial revision
*
***********************************************************************/
/****************************************************************
regalloc.c
The main procedure defined here is reg_alloc which
allocates registers and stack space for a proc exp. After the application of
weights to the body reg_alloc re-codes the number field of each ident within it. Paralloc in paralloc.c does the corresponding work for the
parameters.
At the end of reg_alloc:-
1) props of ident contains inreg_bits or infreg_bits and number = 0
then the value will be in a t reg to be chosen in make_code
2) if props contains the reg bits then number of ident is fixpt s reg
or floatpnt s reg (divided by 2)
3) value is on the stack and:
number of ident = (word displacement in locals)*64 + 29
*****************************************************************/
#include "config.h"
#include "expmacs.h"
#include "tags.h"
#include "procrectypes.h"
#include "bitsmacs.h"
#include "maxminmacs.h"
#include "regable.h"
#include "regmacs.h"
#include "common_types.h"
#include "frames.h"
#include "flags.h"
#include "regalloc.h"
spacereq zerospace = {
0, 0, 0
};
/*****************************************************************
maxspace
Procedure to find the total spacereq of two spacereqs. The bit
representations of the s regs used are simply 'or'ed so that the
resulting dump fields contain all the regs of the parameters.
The largest of the two stack sizes is returned as the stack of the result.
*****************************************************************/
spacereq maxspace
PROTO_N ( (a,b) )
PROTO_T ( spacereq a X spacereq b )
{
a.fixdump |= b.fixdump;
a.fltdump |= b.fltdump;
a.stack = max (a.stack, b.stack);
return a;
}
static int spareparregs = 0;
/******************************************************************
reg_alloc
Delivers a spacereq which gives the local stack bit requirement in the
stack field and the s regs used as bit positions in the fixdump, sdump and
ddump fields for fixed point, single and double floats respectively.
******************************************************************/
spacereq regalloc
PROTO_N ( ( e, freefixed, freefloat, stack) )
PROTO_T ( exp e X int freefixed X int freefloat X long stack )
{
/* e is a proc body . freefixed and
freefloat are the number of fixed and
floating s regs available. These are
initialised at the outer level but may
be reduced by usage in paralloc */
int n = name (e);
exp s = son (e);
spacereq def;
if (n == ident_tag) {
int ffix = freefixed;
int ffloat = freefloat;
long st = stack;
int old_spareparregs = spareparregs;
spacereq body;
ash a;
if (props (e) & defer_bit) {/* the tag declared is transparent to code
production */
def = zerospace;
}
else {
a = ashof (sh (s));
if (name(s) != compound_tag && name(s) != nof_tag
&& name(s) != concatnof_tag ) {
def = regalloc (s, freefixed, freefloat, stack);
}
else { /* elements of tuples are done separately so evaluate above dec */
if (a.ashalign <= 32 || (stack & 0x20) == 0) {
st = stack + ((a.ashsize + 31) & ~31);
}
else {
st = stack + 32 + ((a.ashsize + 31) & ~31);
}
def = regalloc (s, freefixed, freefloat, st);
}
if ((props (e) & inreg_bits) == 0 && fixregable (e) && no (e) < ffix) {
/* suitable for s reg , no(e) has been set
up by weights */
props (e) |= inreg_bits;
if( ffix == 9) {
no(e)=30;
def.fixdump |= (1 << 14);
}
else {
no (e) = ffix + 15; /* will be in s reg , note s0 = $16 */
def.fixdump |= (1 << (ffix-1));
}
ffix -= 1;
}
else
if ((props (e) & infreg_bits) == 0
&& floatregable (e) && no (e) < ffloat) {
/* suitable for float s reg , no(e) has
been set up by weights */
props (e) |= infreg_bits;
no (e) = ffloat + 9; /* will be in s reg , note start from $f20 */
ffloat -= 1;
def.fltdump |= (3 << (ffloat << 1));
}
else
if ((props (e) & inanyreg) == 0) {
if( fixregable(e) && PossParReg(e) && spareparregs > 0) {
props(e) |= inreg_bits;
no(e) = 0;
spareparregs--;
}
else
/* not suitable for reg allocation */
if (name (son (e)) == val_tag && !isvar (e) && !isvis(e)) {
/* must have been forced by const- replace
uses by the value */
exp t = pt (e);
for (; t != nilexp;) {
exp p = pt (t);
setname (t, val_tag);
son (t) = nilexp;
no (t) = no (son (e));
props (t) = 0;
pt (t) = nilexp;
t = p;
}
pt (e) = nilexp;
props (e) |= defer_bit;
def = zerospace;
}
else
if (name (son (e)) == name_tag && !isvar (e) && !isvis(e)) {
/* must have been forced - defer it */
props (e) |= defer_bit;
def = zerospace;
}
else
if (isparam(e)) {
if (props(son(e)) != 0) {
spareparregs++; /* can use this reg in PossParReg */
}
no(e) = 0;
/* don't know framesize yet; displacement in no(son(e)) */
}
else { /* allocate on stack */
int basereg = (Has_vcallees)?local_reg:((Has_fp)?30:29);
if (a.ashalign <= 32 || (stack & 0x20) == 0) {
st = stack + ((a.ashsize + 31) & ~31);
}
else {
stack += 32;
st = stack + ((a.ashsize + 31) & ~31);
}
def.stack = max (def.stack, st);
no (e) = stack * 2 + basereg;
}
}
else
if (no (e) == 101) {
no (e) = ((props (e) & inreg_bits) != 0) ? 2 : 16;
/* set up result of proc as declared id ($f16 = $f0 later)
*/
}
/* else allocation of stack like regs in make_code */
}
body = regalloc (bro (s), ffix, ffloat, st);
spareparregs = old_spareparregs;
return maxspace (body, def);
}
else /* recurse on all expressions in tree */
if (n == case_tag) {
return regalloc (s, freefixed, freefloat, stack);
}
else
if (n != name_tag && n!= env_offset_tag
&& n!= general_env_offset_tag && s != nilexp) {
def = regalloc (s, freefixed, freefloat, stack);
while (!last (s)) {
s = bro (s);
def = maxspace (def, regalloc (s, freefixed, freefloat, stack));
}
return def;
}
else {
def = zerospace;
def.stack = stack;
return def;
}
}