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Evaluate shift index after shift operand because 

the chift operand may use the index register itself.
This commit is contained in:
steve 2002-12-20 01:11:14 +00:00
parent 6fbfdd8f3f
commit 42b34c2ce6
1 changed files with 61 additions and 50 deletions
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111
tgt-vvp/eval_expr.c
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@ -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 1.87 2002/12/19 23:11:29 steve Exp $"
#ident "$Id: eval_expr.c,v 1.88 2002/12/20 01:11:14 steve Exp $"
#endif
# include "vvp_priv.h"
@ -618,9 +618,62 @@ static struct vector_info draw_binary_expr_lrs(ivl_expr_t exp, unsigned wid)
{
ivl_expr_t le = ivl_expr_oper1(exp);
ivl_expr_t re = ivl_expr_oper2(exp);
const char*opcode = "?";
struct vector_info lv;
/* Evaluate the expression that is to be shifted. */
switch (ivl_expr_opcode(exp)) {
case 'l': /* << (left shift) */
lv = draw_eval_expr_wid(le, wid, 0);
/* shifting 0 gets 0. */
if (lv.base == 0)
break;
if (lv.base < 4) {
struct vector_info tmp;
tmp.base = allocate_vector(lv.wid);
tmp.wid = lv.wid;
fprintf(vvp_out, " %%mov %u, %u, %u;\n",
tmp.base, lv.base, lv.wid);
lv = tmp;
}
opcode = "%shiftl";
break;
case 'r': /* >> (unsigned right shift) */
/* with the right shift, there may be high bits that are
shifted into the desired width of the expression, so
we let the expression size itself, if it is bigger
then what is requested of us. */
if (wid > ivl_expr_width(le)) {
lv = draw_eval_expr_wid(le, wid, 0);
} else {
lv = draw_eval_expr_wid(le, ivl_expr_width(le), 0);
}
/* shifting 0 gets 0. */
if (lv.base == 0)
break;
if (lv.base < 4) {
struct vector_info tmp;
tmp.base = allocate_vector(lv.wid);
tmp.wid = lv.wid;
fprintf(vvp_out, " %%mov %u, %u, %u;\n",
tmp.base, lv.base, lv.wid);
lv = tmp;
}
opcode = "%shiftr";
break;
default:
assert(0);
}
/* Figure out the shift amount and load that into the index
register. The value may be a constant, or may need to be
evaluated at run time. */
@ -662,56 +715,10 @@ static struct vector_info draw_binary_expr_lrs(ivl_expr_t exp, unsigned wid)
}
switch (ivl_expr_opcode(exp)) {
fprintf(vvp_out, " %s/i0 %u, %u;\n", opcode, lv.base, lv.wid);
case 'l': /* << (left shift) */
lv = draw_eval_expr_wid(le, wid, 0);
/* shifting 0 gets 0. */
if (lv.base == 0)
break;
if (lv.base < 4) {
struct vector_info tmp;
tmp.base = allocate_vector(lv.wid);
tmp.wid = lv.wid;
fprintf(vvp_out, " %%mov %u, %u, %u;\n",
tmp.base, lv.base, lv.wid);
lv = tmp;
}
fprintf(vvp_out, " %%shiftl/i0 %u, %u;\n", lv.base, lv.wid);
break;
case 'r': /* >> (unsigned right shift) */
/* with the right shift, there may be high bits that are
shifted into the desired width of the expression, so
we let the expression size itself, if it is bigger
then what is requested of us. */
if (wid > ivl_expr_width(le)) {
lv = draw_eval_expr_wid(le, wid, 0);
} else {
lv = draw_eval_expr_wid(le, ivl_expr_width(le), 0);
}
/* shifting 0 gets 0. */
if (lv.base == 0)
break;
if (lv.base < 4) {
struct vector_info tmp;
tmp.base = allocate_vector(lv.wid);
tmp.wid = lv.wid;
fprintf(vvp_out, " %%mov %u, %u, %u;\n",
tmp.base, lv.base, lv.wid);
lv = tmp;
}
fprintf(vvp_out, " %%shiftr/i0 %u, %u;\n", lv.base, lv.wid);
break;
default:
assert(0);
}
if (lv.base >= 8)
save_expression_lookaside(lv.base, exp, lv.wid);
return lv;
}
@ -1963,6 +1970,10 @@ struct vector_info draw_eval_expr(ivl_expr_t exp, int stuff_ok_flag)
/*
* $Log: eval_expr.c,v $
* Revision 1.88 2002/12/20 01:11:14 steve
* Evaluate shift index after shift operand because
* the chift operand may use the index register itself.
*
* Revision 1.87 2002/12/19 23:11:29 steve
* Keep bit select subexpression width if it is constant.
*