iverilog/tgt-vvp/eval_real.c

304 lines
7.0 KiB
C

/*
* Copyright (c) 2003-2010 Stephen Williams (steve@icarus.com)
*
* This source code is free software; you can redistribute it
* and/or modify it in source code form under the terms of the GNU
* General Public License as published by the Free Software
* Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
/*
* This file includes functions for evaluating REAL expressions.
*/
# include "vvp_priv.h"
# include <string.h>
#ifdef HAVE_MALLOC_H
# include <malloc.h>
#endif
# include <stdlib.h>
# include <math.h>
# include <assert.h>
static unsigned long word_alloc_mask = 0x0f;
int allocate_word()
{
int res = 4;
int max = 8*sizeof(word_alloc_mask);
while (res < max && (1U << res) & word_alloc_mask)
res += 1;
assert(res < max);
word_alloc_mask |= 1U << res;
return res;
}
void clr_word(int res)
{
int max = 8*sizeof(word_alloc_mask);
assert(res < max);
word_alloc_mask &= ~ (1U << res);
}
static int draw_binary_real(ivl_expr_t exp)
{
int l, r = -1;
l = draw_eval_real(ivl_expr_oper1(exp));
r = draw_eval_real(ivl_expr_oper2(exp));
switch (ivl_expr_opcode(exp)) {
case '+':
fprintf(vvp_out, " %%add/wr %d, %d;\n", l, r);
break;
case '-':
fprintf(vvp_out, " %%sub/wr %d, %d;\n", l, r);
break;
case '*':
fprintf(vvp_out, " %%mul/wr %d, %d;\n", l, r);
break;
case '/':
fprintf(vvp_out, " %%div/wr %d, %d;\n", l, r);
break;
case '%':
{ struct vector_info res = draw_eval_expr(exp, STUFF_OK_XZ);
l = allocate_word();
fprintf(vvp_out, " %%ix/get %d, %u, %u;\n",
l, res.base, res.wid);
fprintf(vvp_out, " %%cvt/ri %d, %d;\n", l, l);
clr_vector(res);
}
break;
default:
fprintf(stderr, "XXXX draw_binary_real(%c)\n",
ivl_expr_opcode(exp));
assert(0);
}
if (r >= 0) clr_word(r);
return l;
}
static int draw_number_real(ivl_expr_t exp)
{
unsigned int idx;
int res = allocate_word();
const char*bits = ivl_expr_bits(exp);
unsigned wid = ivl_expr_width(exp);
unsigned long mant = 0;
int vexp = 0x1000;
for (idx = 0 ; idx < wid ; idx += 1) {
if (bits[idx] == '1')
mant |= 1 << idx;
}
/* If this is actually a negative number, then get the
positive equivalent, and set the sign bit in the exponent
field. */
if (ivl_expr_signed(exp) && (bits[wid-1] == '1')) {
mant = (0-mant) & ((1UL<<wid) - 1UL);
vexp |= 0x4000;
}
fprintf(vvp_out, " %%loadi/wr %d, %lu, %d; load(num)= %c%lu\n",
res, mant, vexp, (vexp&0x4000)? '-' : '+', mant);
return res;
}
/*
* Evaluate a real variable expression by loading the real variable
* into a real thread word.
*/
static int draw_variable_real(ivl_expr_t exp)
{
int res = allocate_word();
ivl_variable_t var = ivl_expr_variable(exp);
fprintf(vvp_out, " %%load/wr %d, W_%s;\n", res, vvp_word_label(var));
return res;
}
static int draw_realnum_real(ivl_expr_t exp)
{
int res = allocate_word();
double value = ivl_expr_dvalue(exp);
double fract;
int expo, vexp;
unsigned long mant;
int sign = 0;
if (value < 0) {
sign = 0x4000;
value *= -1;
}
fract = frexp(value, &expo);
fract = ldexp(fract, 31);
mant = fract;
expo -= 31;
vexp = expo + 0x1000;
assert(vexp >= 0);
assert(vexp < 0x2000);
vexp += sign;
fprintf(vvp_out, " %%loadi/wr %d, %lu, %d; load=%f\n",
res, mant, vexp, ivl_expr_dvalue(exp));
/* Capture the residual bits, if there are any. Note that an
IEEE754 mantissa has 52 bits, 31 of which were accounted
for already. */
fract -= floor(fract);
fract = ldexp(fract, 22);
mant = fract;
expo -= 22;
vexp = expo + 0x1000;
assert(vexp >= 0);
assert(vexp < 0x2000);
vexp += sign;
if (mant != 0) {
int tmp_word = allocate_word();
fprintf(vvp_out, " %%loadi/wr %d, %lu, %d; load=%f\n",
tmp_word, mant, vexp, ivl_expr_dvalue(exp));
fprintf(vvp_out, " %%add/wr %d, %d;\n", res, tmp_word);
clr_word(tmp_word);
}
return res;
}
static int draw_sfunc_real(ivl_expr_t exp)
{
struct vector_info sv;
int res;
switch (ivl_expr_value(exp)) {
case IVL_VT_REAL:
if (ivl_expr_parms(exp) == 0) {
res = allocate_word();
fprintf(vvp_out, " %%vpi_func/r \"%s\", %d;\n",
ivl_expr_name(exp), res);
} else {
res = draw_vpi_rfunc_call(exp);
}
break;
case IVL_VT_VECTOR:
/* If the value of the sfunc is a vector, then evaluate
it as a vector, then convert the result to a real
(via an index register) for the result. */
sv = draw_eval_expr(exp, 0);
clr_vector(sv);
res = allocate_word();
fprintf(vvp_out, " %%ix/get %d, %u, %u;\n",
res, sv.base, sv.wid);
fprintf(vvp_out, " %%cvt/ri %d, %d;\n", res, res);
break;
default:
assert(0);
res = -1;
}
return res;
}
/*
* The real value of a signal is the integer value of a signal
* converted to real.
*/
static int draw_signal_real(ivl_expr_t exp)
{
int res = allocate_word();
struct vector_info sv = draw_eval_expr(exp, 0);
fprintf(vvp_out, " %%ix/get %d, %u, %u;\n", res, sv.base, sv.wid);
clr_vector(sv);
fprintf(vvp_out, " %%cvt/ri %d, %d;\n", res, res);
return res;
}
int draw_eval_real(ivl_expr_t exp)
{
int res = 0;
switch (ivl_expr_type(exp)) {
case IVL_EX_BINARY:
res = draw_binary_real(exp);
break;
case IVL_EX_NUMBER:
res = draw_number_real(exp);
break;
case IVL_EX_REALNUM:
res = draw_realnum_real(exp);
break;
case IVL_EX_VARIABLE:
res = draw_variable_real(exp);
break;
case IVL_EX_SFUNC:
res = draw_sfunc_real(exp);
break;
case IVL_EX_SIGNAL:
res = draw_signal_real(exp);
break;
default:
if (ivl_expr_value(exp) == IVL_VT_VECTOR) {
struct vector_info sv = draw_eval_expr(exp, 0);
clr_vector(sv);
res = allocate_word();
fprintf(vvp_out, " %%ix/get %d, %u, %u;\n", res,
sv.base, sv.wid);
fprintf(vvp_out, " %%cvt/ri %d, %d;\n", res, res);
} else {
fprintf(stderr, "XXXX Evaluate real expression (%d)\n",
ivl_expr_type(exp));
fprintf(vvp_out, " ; XXXX Evaluate real expression (%d)\n",
ivl_expr_type(exp));
return 0;
}
break;
}
return res;
}