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More robust use of precalculated expressions, and
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 Separate lookaside for written variables that can
 also be reused.
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steve committed Sep 17, 2005
1 parent 7235706 commit 672aa61
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Showing 4 changed files with 171 additions and 57 deletions.
48 changes: 33 additions & 15 deletions tgt-vvp/eval_expr.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#ifdef HAVE_CVS_IDENT
#ident "$Id: eval_expr.c,v 1.121 2005/09/15 02:49:47 steve Exp $"
#ident "$Id: eval_expr.c,v 1.122 2005/09/17 01:01:00 steve Exp $"
#endif

# include "vvp_priv.h"
Expand Down Expand Up @@ -274,8 +274,8 @@ static struct vector_info draw_binary_expr_eq(ivl_expr_t exp,
if (ivl_expr_width(re) > wid)
wid = ivl_expr_width(re);

lv = draw_eval_expr_wid(le, wid, stuff_ok_flag&STUFF_OK_XZ);
rv = draw_eval_expr_wid(re, wid, stuff_ok_flag&STUFF_OK_XZ);
lv = draw_eval_expr_wid(le, wid, stuff_ok_flag&~STUFF_OK_47);
rv = draw_eval_expr_wid(re, wid, stuff_ok_flag&~STUFF_OK_47);

switch (ivl_expr_opcode(exp)) {
case 'E': /* === */
Expand Down Expand Up @@ -1057,7 +1057,7 @@ static struct vector_info draw_binary_expr_arith(ivl_expr_t exp, unsigned wid)
return draw_mul_immediate(le, re, wid);

lv = draw_eval_expr_wid(le, wid, STUFF_OK_XZ);
rv = draw_eval_expr_wid(re, wid, STUFF_OK_XZ);
rv = draw_eval_expr_wid(re, wid, STUFF_OK_XZ|STUFF_OK_RO);

if (lv.wid != wid) {
fprintf(stderr, "XXXX ivl_expr_opcode(exp) = %c,"
Expand Down Expand Up @@ -1198,11 +1198,14 @@ static struct vector_info draw_binary_expr(ivl_expr_t exp,
* expression, then copying it into the continguous vector of the
* result. Do this until the result vector is filled.
*/
static struct vector_info draw_concat_expr(ivl_expr_t exp, unsigned wid)
static struct vector_info draw_concat_expr(ivl_expr_t exp, unsigned wid,
int stuff_ok_flag)
{
unsigned off, rep;
struct vector_info res;

int alloc_exclusive = (stuff_ok_flag&STUFF_OK_RO) ? 0 : 1;

/* Allocate a vector to hold the result. */
res.base = allocate_vector(wid);
res.wid = wid;
Expand Down Expand Up @@ -1232,7 +1235,7 @@ static struct vector_info draw_concat_expr(ivl_expr_t exp, unsigned wid)

/* Try to locate the subexpression in the
lookaside map. */
avec.base = allocate_vector_exp(arg, awid);
avec.base = allocate_vector_exp(arg, awid, alloc_exclusive);
avec.wid = awid;

trans = awid;
Expand Down Expand Up @@ -1517,15 +1520,21 @@ static void draw_signal_dest(ivl_expr_t exp, struct vector_info res)
}
}

static struct vector_info draw_signal_expr(ivl_expr_t exp, unsigned wid)
static struct vector_info draw_signal_expr(ivl_expr_t exp, unsigned wid,
int stuff_ok_flag)
{
struct vector_info res;

int alloc_exclusive = (stuff_ok_flag&STUFF_OK_RO) ? 0 : 1;

/* Already in the vector lookaside? */
res.base = allocate_vector_exp(exp, wid);
res.base = allocate_vector_exp(exp, wid, alloc_exclusive);
res.wid = wid;
if (res.base != 0)
if (res.base != 0) {
fprintf(vvp_out, "; Reuse signal base=%u wid=%u from lookaside.\n",
res.base, res.wid);
return res;
}

res.base = allocate_vector(wid);
res.wid = wid;
Expand Down Expand Up @@ -1643,16 +1652,19 @@ static struct vector_info draw_select_signal(ivl_expr_t sube,
return res;
}

static struct vector_info draw_select_expr(ivl_expr_t exp, unsigned wid)
static struct vector_info draw_select_expr(ivl_expr_t exp, unsigned wid,
int stuff_ok_flag)
{
struct vector_info subv, shiv, res;
ivl_expr_t sube = ivl_expr_oper1(exp);
ivl_expr_t shift = ivl_expr_oper2(exp);

int alloc_exclusive = (stuff_ok_flag&STUFF_OK_RO)? 0 : 1;

/* First look for the self expression in the lookaside, and
allocate that if possible. If I find it, then immediatly
return that. */
if ( (res.base = allocate_vector_exp(exp, wid)) != 0) {
if ( (res.base = allocate_vector_exp(exp, wid, alloc_exclusive)) != 0) {
fprintf(vvp_out, "; Reuse base=%u wid=%u from lookaside.\n",
res.base, wid);
res.wid = wid;
Expand Down Expand Up @@ -1712,6 +1724,7 @@ static struct vector_info draw_select_expr(ivl_expr_t exp, unsigned wid)
res.wid = wid;

subv.base += wid;
subv.wid -= wid;
clr_vector(subv);

} else if (subv.wid == wid) {
Expand Down Expand Up @@ -1742,7 +1755,7 @@ static struct vector_info draw_ternary_expr(ivl_expr_t exp, unsigned wid)

/* Evaluate the condition expression, and if necessary reduce
it to a single bit. */
tst = draw_eval_expr(cond, STUFF_OK_XZ);
tst = draw_eval_expr(cond, STUFF_OK_XZ|STUFF_OK_RO);
if ((tst.base >= 4) && (tst.wid > 1)) {
struct vector_info tmp;

Expand Down Expand Up @@ -2064,7 +2077,7 @@ struct vector_info draw_eval_expr_wid(ivl_expr_t exp, unsigned wid,
break;

case IVL_EX_CONCAT:
res = draw_concat_expr(exp, wid);
res = draw_concat_expr(exp, wid, stuff_ok_flag);
break;

case IVL_EX_NUMBER:
Expand All @@ -2079,11 +2092,11 @@ struct vector_info draw_eval_expr_wid(ivl_expr_t exp, unsigned wid,
if (ivl_expr_oper2(exp) == 0)
res = draw_pad_expr(exp, wid);
else
res = draw_select_expr(exp, wid);
res = draw_select_expr(exp, wid, stuff_ok_flag);
break;

case IVL_EX_SIGNAL:
res = draw_signal_expr(exp, wid);
res = draw_signal_expr(exp, wid, stuff_ok_flag);
break;

case IVL_EX_TERNARY:
Expand Down Expand Up @@ -2117,6 +2130,11 @@ struct vector_info draw_eval_expr(ivl_expr_t exp, int stuff_ok_flag)

/*
* $Log: eval_expr.c,v $
* Revision 1.122 2005/09/17 01:01:00 steve
* More robust use of precalculated expressions, and
* Separate lookaside for written variables that can
* also be reused.
*
* Revision 1.121 2005/09/15 02:49:47 steve
* Better reuse of IVL_EX_SELECT expressions.
*
Expand Down
132 changes: 95 additions & 37 deletions tgt-vvp/vector.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#ifdef HAVE_CVS_IDENT
#ident "$Id: vector.c,v 1.6 2005/09/15 02:50:13 steve Exp $"
#ident "$Id: vector.c,v 1.7 2005/09/17 01:01:00 steve Exp $"
#endif

# include "vvp_priv.h"
Expand All @@ -31,42 +31,35 @@

static struct allocation_score_s {
ivl_expr_t exp;
unsigned bit;
unsigned alloc : 1;
ivl_signal_t sig;
unsigned exp_bit : 24;
unsigned sig_bit : 24;
unsigned alloc : 8;
} allocation_map[MAX_VEC] = { {0} };

/* This is the largest bit to have lookaside values. */
static unsigned lookaside_top = 0;

static inline int peek_bit(unsigned addr)
{
return allocation_map[addr].alloc;
}

static inline void set_bit(unsigned addr)
{
allocation_map[addr].alloc = 1;
}

static inline void clr_bit(unsigned addr)
{
allocation_map[addr].alloc = 0;
}

static inline ivl_expr_t peek_exp(unsigned addr)
{
return allocation_map[addr].exp;
}

static inline unsigned peek_exp_bit(unsigned addr)
{
return allocation_map[addr].bit;
return allocation_map[addr].exp_bit;
}

static inline void set_exp(unsigned addr, ivl_expr_t exp, unsigned ebit)
{
allocation_map[addr].exp = exp;
allocation_map[addr].bit = ebit;
allocation_map[addr].exp_bit = ebit;
}

static inline void set_sig(unsigned addr, ivl_signal_t exp, unsigned ebit)
{
allocation_map[addr].sig = exp;
allocation_map[addr].sig_bit = ebit;
}

/*
Expand All @@ -84,8 +77,10 @@ void clr_vector(struct vector_info vec)
if (vec.base < 4)
return;
assert(vec.base >= 8);
for (idx = 0 ; idx < vec.wid ; idx += 1)
clr_bit(vec.base + idx);
for (idx = 0 ; idx < vec.wid ; idx += 1) {
assert( allocation_map[vec.base+idx].alloc > 0);
allocation_map[vec.base+idx].alloc -= 1;
}
}

static unsigned allocate_vector_no_lookaside(unsigned wid, int skip_lookaside)
Expand All @@ -95,7 +90,8 @@ static unsigned allocate_vector_no_lookaside(unsigned wid, int skip_lookaside)

while (idx < wid) {
assert((base + idx) < MAX_VEC);
if (peek_bit(base+idx) || (skip_lookaside && peek_exp(base+idx))) {
if ((allocation_map[base+idx].alloc > 0)
|| (skip_lookaside && peek_exp(base+idx))) {
base = base + idx + 1;
idx = 0;

Expand All @@ -105,7 +101,7 @@ static unsigned allocate_vector_no_lookaside(unsigned wid, int skip_lookaside)
}

for (idx = 0 ; idx < wid ; idx += 1) {
set_bit(base+idx);
allocation_map[base+idx].alloc += 1;
set_exp(base+idx, 0, 0);
}

Expand Down Expand Up @@ -140,21 +136,45 @@ unsigned allocate_vector(unsigned wid)
void clear_expression_lookaside(void)
{
unsigned idx;
for (idx = 0 ; idx < lookaside_top ; idx += 1)

for (idx = 0 ; idx < lookaside_top ; idx += 1) {
set_exp(idx, 0, 0);
set_sig(idx, 0, 0);
}

lookaside_top = 0;
}

void save_expression_lookaside(unsigned addr, ivl_expr_t exp,
unsigned wid)
void save_expression_lookaside(unsigned addr, ivl_expr_t exp, unsigned wid)
{
unsigned idx;
assert(addr >= 8);
assert((addr+wid) <= MAX_VEC);

for (idx = 0 ; idx < wid ; idx += 1)
/* When saving an expression to the lookaside, also clear the
signal saved in the lookaside for these bits. The reason is
that an expression calculation will replace any signal
bits. */
for (idx = 0 ; idx < wid ; idx += 1) {
set_exp(addr+idx, exp, idx);
set_sig(addr+idx, 0, 0);
}

if ((addr+wid) > lookaside_top)
lookaside_top = addr+wid;
}

void save_signal_lookaside(unsigned addr, ivl_signal_t sig, unsigned wid)
{
unsigned idx;
/* Don't bind any of hte low bits to a signal. */
if (addr < 8)
return;

assert((addr+wid) <= MAX_VEC);

for (idx = 0 ; idx < wid ; idx += 1)
set_sig(addr+idx, sig, idx);

if ((addr+wid) > lookaside_top)
lookaside_top = addr+wid;
Expand Down Expand Up @@ -213,26 +233,56 @@ static int compare_exp(ivl_expr_t l, ivl_expr_t r)
return 0;
}

static unsigned find_expression_lookaside(ivl_expr_t exp,
unsigned wid)
static unsigned find_expression_lookaside(ivl_expr_t exp, unsigned wid)
{
unsigned top;
unsigned idx, match;
ivl_signal_t sig;

if (lookaside_top <= wid)
return 0;

top = lookaside_top - wid + 1;

/* Look in the expression lookaside for this expression. */
assert(exp);
match = 0;
for (idx = 8 ; idx < top ; idx += 1) {
for (idx = 8 ; idx < lookaside_top ; idx += 1) {
if (! compare_exp(allocation_map[idx].exp, exp)) {
match = 0;
continue;
}

if (allocation_map[idx].bit != match) {
if (allocation_map[idx].exp_bit != match) {
match = 0;
continue;
}

match += 1;
if (match == wid)
return idx-match+1;
}

if (ivl_expr_type(exp) != IVL_EX_SIGNAL)
return 0;

sig = ivl_expr_signal(exp);

/* Only reg signals (variables) will be in the signal
lookaside, because only blocking assigned values are in the
signal lookaside. */
if (ivl_signal_type(sig) != IVL_SIT_REG)
return 0;

/* Now look for signal value matches in the signal lookaside. */
match = 0;
for (idx = 8 ; idx < lookaside_top ; idx += 1) {
if (sig != allocation_map[idx].sig) {
match = 0;
continue;
}

if (allocation_map[idx].sig_bit != match) {
match = 0;
continue;
}
Expand All @@ -251,23 +301,31 @@ static unsigned find_expression_lookaside(ivl_expr_t exp,
* caller will not need to evaluate the expression. If this function
* returns 0, then the expression is not found and nothing is allocated.
*/
unsigned allocate_vector_exp(ivl_expr_t exp, unsigned wid)
unsigned allocate_vector_exp(ivl_expr_t exp, unsigned wid,
int exclusive_flag)
{
unsigned idx;
unsigned la = find_expression_lookaside(exp, wid);

for (idx = 0 ; idx < wid ; idx += 1)
if (allocation_map[la+idx].alloc)
return 0;
if (exclusive_flag) {
for (idx = 0 ; idx < wid ; idx += 1)
if (allocation_map[la+idx].alloc)
return 0;
}

for (idx = 0 ; idx < wid ; idx += 1)
allocation_map[la+idx].alloc = 1;
allocation_map[la+idx].alloc += 1;

return la;
}

/*
* $Log: vector.c,v $
* Revision 1.7 2005/09/17 01:01:00 steve
* More robust use of precalculated expressions, and
* Separate lookaside for written variables that can
* also be reused.
*
* Revision 1.6 2005/09/15 02:50:13 steve
* Preserve precalculated expressions when possible.
*
Expand Down
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