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#include <assert.h>
#include "regnaive.h"
typedef struct reg_alloc_t reg_alloc_t;
typedef struct reg_pool_t reg_pool_t;
#define MAX_REGISTERS (16)
#define MAX_SPILLS (16)
static int
find_index (reg_alloc_t *ra, reg_t reg)
{
int i;
for (i = 0; i < ra->pool->n_registers; ++i)
{
if (ra->pool->registers[i] == reg)
return i;
}
assert (0);
return -1;
}
void
reg_alloc_init (reg_alloc_t *ra,
const reg_pool_t *reg_pool)
{
int i;
ra->pool = reg_pool;
for (i = 0; i < ra->pool->n_registers; ++i)
{
ra->allocated[i] = FALSE;
ra->clobbered[i] = FALSE;
}
ra->failed = FALSE;
}
/* This resurrects a register that has been freed, but is known
* to still contain a useful value.
*/
reg_t
reg_alloc_alloc_preserve (reg_alloc_t *ra, reg_t reg)
{
int idx = find_index (ra, reg);
assert (!ra->allocated[idx]);
ra->allocated[idx] = TRUE;
ra->clobbered[idx] = TRUE;
return reg;
}
reg_t
reg_alloc_alloc (reg_alloc_t *ra)
{
int i;
for (i = 0; i < ra->pool->n_registers; ++i)
{
if (!ra->allocated[i])
{
ra->allocated[i] = TRUE;
ra->clobbered[i] = TRUE;
return ra->pool->registers[i];
}
}
ra->failed = TRUE;
return (reg_t)0;
}
void
reg_alloc_free (reg_alloc_t *ra, reg_t reg)
{
int idx = find_index (ra, reg);
assert (ra->allocated[idx]);
ra->allocated[idx] = FALSE;
}
int
reg_alloc_failed (reg_alloc_t *ra)
{
return ra->failed;
}
int
reg_alloc_clobbered (reg_alloc_t *ra, reg_t reg)
{
int idx = find_index (ra, reg);
return ra->clobbered[idx];
}
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