/*
* This function handles the case of non-blocking assign to word
* variables such as real, i.e:
*
* read foo;
* foo <= 1.0;
*
* In this case we know (by Verilog syntax) that there is only exactly
* 1 l-value, the target identifier, so it should be relatively easy.
*/
static int show_stmt_assign_nb_var(ivl_statement_t net)
{
ivl_lval_t lval;
ivl_variable_t var;
ivl_expr_t rval = ivl_stmt_rval(net);
ivl_expr_t del = ivl_stmt_delay_expr(net);
int word;
unsigned long delay;
/* Must be exactly 1 l-value. */
assert(ivl_stmt_lvals(net) == 1);
delay = 0;
if (del && (ivl_expr_type(del) == IVL_EX_ULONG)) {
delay = ivl_expr_uvalue(del);
del = 0;
}
/* XXXX For now, presume delays are constant. */
assert(del == 0);
/* Evaluate the r-value */
word = draw_eval_real(rval);
lval = ivl_stmt_lval(net, 0);
var = ivl_lval_var(lval);
assert(var != 0);
fprintf(vvp_out, " %%assign/wr W_%s, %lu, %u;\n",
vvp_word_label(var), delay, word);
return 0;
}
/*
* The delayx statement is slightly more complex in that it is
* necessary to calculate the delay first. Load the calculated delay
* into and index register and use the %delayx instruction to do the
* actual delay.
*/
static int show_stmt_delayx(ivl_statement_t net, ivl_scope_t sscope)
{
int rc = 0;
ivl_expr_t exp = ivl_stmt_delay_expr(net);
ivl_statement_t stmt = ivl_stmt_sub_stmt(net);
switch (ivl_expr_value(exp)) {
case IVL_VT_VECTOR: {
struct vector_info del = draw_eval_expr(exp, 0);
fprintf(vvp_out, " %%ix/get 0, %u, %u;\n",
del.base, del.wid);
clr_vector(del);
break;
}
case IVL_VT_REAL: {
int word = draw_eval_real(exp);
fprintf(vvp_out, " %%cvt/ir 0, %d;\n", word);
clr_word(word);
break;
}
default:
assert(0);
}
fprintf(vvp_out, " %%delayx 0;\n");
/* Lots of things can happen during a delay. */
clear_expression_lookaside();
rc += show_statement(stmt, sscope);
return rc;
}
static void emit_stmt_inter_delay(ivl_scope_t scope, ivl_statement_t stmt)
{
ivl_expr_t delay = ivl_stmt_delay_expr(stmt);
unsigned nevents = ivl_stmt_nevent(stmt);
if (nevents) {
ivl_expr_t count = ivl_stmt_cond_expr(stmt);
if (count) {
if (ivl_expr_type(count) == IVL_EX_ULONG) {
unsigned long repeat = ivl_expr_uvalue(count);
if (repeat != 1) {
fprintf(vlog_out, "repeat(%lu) ", repeat);
}
} else {
fprintf(vlog_out, "repeat(");
emit_expr(scope, count, 0);
fprintf(vlog_out, ") ");
}
}
assert(delay == 0);
fprintf(vlog_out, "@(");
emit_event(scope, stmt);
fprintf(vlog_out, ") ");
}
if (delay) {
assert(nevents == 0);
fprintf(vlog_out, "#(");
emit_scaled_delayx(scope, delay, 1);
fprintf(vlog_out, ") ");
}
}
static void emit_stmt_delayx(ivl_scope_t scope, ivl_statement_t stmt)
{
fprintf(vlog_out, "%*c#(", get_indent(), ' ');
emit_scaled_delayx(scope, ivl_stmt_delay_expr(stmt), 1);
fprintf(vlog_out, ")");
emit_stmt_file_line(stmt);
single_indent = 1;
emit_stmt(scope, ivl_stmt_sub_stmt(stmt));
}
static int show_stmt_assign_nb(ivl_statement_t net)
{
ivl_lval_t lval;
ivl_expr_t rval = ivl_stmt_rval(net);
ivl_expr_t del = ivl_stmt_delay_expr(net);
ivl_memory_t mem;
unsigned long delay = 0;
/* Catch the case we are assigning to a real/word
l-value. Handle that elsewhere. */
if (ivl_lval_var(ivl_stmt_lval(net, 0))) {
return show_stmt_assign_nb_var(net);
}
if (del && (ivl_expr_type(del) == IVL_EX_ULONG)) {
delay = ivl_expr_uvalue(del);
del = 0;
}
/* Handle the special case that the r-value is a constant. We
can generate the %set statement directly, without any worry
about generating code to evaluate the r-value expressions. */
if (ivl_expr_type(rval) == IVL_EX_NUMBER) {
unsigned lidx;
const char*bits = ivl_expr_bits(rval);
unsigned wid = ivl_expr_width(rval);
unsigned cur_rbit = 0;
if (del != 0)
calculate_into_x1(del);
for (lidx = 0 ; lidx < ivl_stmt_lvals(net) ; lidx += 1) {
unsigned skip_set = transient_id++;
unsigned skip_set_flag = 0;
unsigned idx;
unsigned bit_limit = wid - cur_rbit;
lval = ivl_stmt_lval(net, lidx);
/* If there is a mux for the lval, calculate the
value and write it into index0. */
if (ivl_lval_mux(lval)) {
calculate_into_x0(ivl_lval_mux(lval));
fprintf(vvp_out, " %%jmp/1 t_%u, 4;\n", skip_set);
skip_set_flag = 1;
}
mem = ivl_lval_mem(lval);
if (mem) {
draw_memory_index_expr(mem, ivl_lval_idx(lval));
fprintf(vvp_out, " %%jmp/1 t_%u, 4;\n", skip_set);
skip_set_flag = 1;
}
if (bit_limit > ivl_lval_pins(lval))
bit_limit = ivl_lval_pins(lval);
if (mem) {
for (idx = 0 ; idx < bit_limit ; idx += 1) {
assign_to_memory(mem, idx,
bitchar_to_idx(bits[cur_rbit]),
delay);
cur_rbit += 1;
}
for (idx = bit_limit
; idx < ivl_lval_pins(lval)
; idx += 1) {
assign_to_memory(mem, idx, 0, delay);
}
} else if ((del == 0) && (bit_limit > 2)) {
/* We have a vector, but no runtime
calculated delays, to try to use vector
assign instructions. */
idx = 0;
while (idx < bit_limit) {
unsigned wid = 0;
do {
wid += 1;
if ((idx + wid) == bit_limit)
break;
} while (bits[cur_rbit] == bits[cur_rbit+wid]);
switch (wid) {
case 1:
assign_to_lvariable(lval, idx,
bitchar_to_idx(bits[cur_rbit]),
delay, 0);
break;
case 2:
assign_to_lvariable(lval, idx,
bitchar_to_idx(bits[cur_rbit]),
delay, 0);
assign_to_lvariable(lval, idx+1,
bitchar_to_idx(bits[cur_rbit]),
delay, 0);
break;
default:
assign_to_lvector(lval, idx,
bitchar_to_idx(bits[cur_rbit]),
delay, wid);
break;
}
idx += wid;
cur_rbit += wid;
}
if (bit_limit < ivl_lval_pins(lval)) {
unsigned wid = ivl_lval_pins(lval) - bit_limit;
assign_to_lvector(lval, bit_limit,
0, delay, wid);
}
} else {
for (idx = 0 ; idx < bit_limit ; idx += 1) {
if (del != 0)
assign_to_lvariable(lval, idx,
bitchar_to_idx(bits[cur_rbit]),
1, 1);
else
assign_to_lvariable(lval, idx,
bitchar_to_idx(bits[cur_rbit]),
delay, 0);
cur_rbit += 1;
}
for (idx = bit_limit
; idx < ivl_lval_pins(lval)
; idx += 1) {
if (del != 0)
assign_to_lvariable(lval, idx, 0,
1, 1);
else
assign_to_lvariable(lval, idx, 0,
delay, 0);
}
}
if (skip_set_flag) {
fprintf(vvp_out, "t_%u ;\n", skip_set);
clear_expression_lookaside();
}
}
return 0;
}
{ struct vector_info res = draw_eval_expr(rval, 0);
unsigned wid = res.wid;
unsigned lidx;
unsigned cur_rbit = 0;
if (del != 0)
calculate_into_x1(del);
for (lidx = 0 ; lidx < ivl_stmt_lvals(net) ; lidx += 1) {
unsigned skip_set = transient_id++;
unsigned skip_set_flag = 0;
unsigned idx;
unsigned bit_limit = wid - cur_rbit;
lval = ivl_stmt_lval(net, lidx);
/* If there is a mux for the lval, calculate the
value and write it into index0. */
if (ivl_lval_mux(lval)) {
calculate_into_x0(ivl_lval_mux(lval));
fprintf(vvp_out, " %%jmp/1 t_%u, 4;\n", skip_set);
skip_set_flag = 1;
}
mem = ivl_lval_mem(lval);
if (mem) {
draw_memory_index_expr(mem, ivl_lval_idx(lval));
fprintf(vvp_out, " %%jmp/1 t_%u, 4;\n", skip_set);
skip_set_flag = 1;
}
if (bit_limit > ivl_lval_pins(lval))
bit_limit = ivl_lval_pins(lval);
if ((bit_limit > 2) && (mem == 0) && (del == 0)) {
unsigned bidx = res.base < 4
? res.base
: (res.base+cur_rbit);
assign_to_lvector(lval, 0, bidx, delay, bit_limit);
cur_rbit += bit_limit;
} else {
for (idx = 0 ; idx < bit_limit ; idx += 1) {
unsigned bidx = res.base < 4
? res.base
: (res.base+cur_rbit);
if (mem)
assign_to_memory(mem, idx, bidx, delay);
else if (del != 0)
assign_to_lvariable(lval, idx, bidx,
1, 1);
else
assign_to_lvariable(lval, idx, bidx,
delay, 0);
cur_rbit += 1;
}
}
for (idx = bit_limit; idx < ivl_lval_pins(lval); idx += 1)
if (mem)
assign_to_memory(mem, idx, 0, delay);
else if (del != 0)
assign_to_lvariable(lval, idx, 0, 1, 1);
else
assign_to_lvariable(lval, idx, 0, delay, 0);
if (skip_set_flag) {
fprintf(vvp_out, "t_%u ;\n", skip_set);
clear_expression_lookaside();
}
}
if (res.base > 3)
clr_vector(res);
}
return 0;
}
/*
* Icarus translated <var> = <delay or event> <value> into
* begin
* <tmp> = <value>;
* <delay or event> <var> = <tmp>;
* end
* This routine looks for this pattern and turns it back into the
* appropriate blocking assignment.
*/
static unsigned is_delayed_or_event_assign(ivl_scope_t scope,
ivl_statement_t stmt)
{
unsigned wid;
ivl_statement_t assign, delay, delayed_assign;
ivl_statement_type_t delay_type;
ivl_lval_t lval;
ivl_expr_t rval;
ivl_signal_t lsig, rsig;
/* We must have two block elements. */
if (ivl_stmt_block_count(stmt) != 2) return 0;
/* The first must be an assign. */
assign = ivl_stmt_block_stmt(stmt, 0);
if (ivl_statement_type(assign) != IVL_ST_ASSIGN) return 0;
/* The second must be a delayx. */
delay = ivl_stmt_block_stmt(stmt, 1);
delay_type = ivl_statement_type(delay);
if ((delay_type != IVL_ST_DELAYX) &&
(delay_type != IVL_ST_WAIT)) return 0;
/* The statement for the delayx must be an assign. */
delayed_assign = ivl_stmt_sub_stmt(delay);
if (ivl_statement_type(delayed_assign) != IVL_ST_ASSIGN) return 0;
/* The L-value must be a single signal. */
if (ivl_stmt_lvals(assign) != 1) return 0;
lval = ivl_stmt_lval(assign, 0);
/* It must not have an array select. */
if (ivl_lval_idx(lval)) return 0;
/* It must not have a non-zero base. */
if (ivl_lval_part_off(lval)) return 0;
lsig = ivl_lval_sig(lval);
/* It must not be part of the signal. */
if (ivl_lval_width(lval) != ivl_signal_width(lsig)) return 0;
/* The R-value must be a single signal. */
rval = ivl_stmt_rval(delayed_assign);
if (ivl_expr_type(rval) != IVL_EX_SIGNAL) return 0;
/* It must not be an array word. */
if (ivl_expr_oper1(rval)) return 0;
rsig = ivl_expr_signal(rval);
/* The two signals must be the same. */
if (lsig != rsig) return 0;
/* And finally the three statements must have the same line number
* as the block. */
if ((ivl_stmt_lineno(stmt) != ivl_stmt_lineno(assign)) ||
(ivl_stmt_lineno(stmt) != ivl_stmt_lineno(delay)) ||
(ivl_stmt_lineno(stmt) != ivl_stmt_lineno(delayed_assign))) {
return 0;
}
/* The pattern matched so generate the appropriate code. */
fprintf(vlog_out, "%*c", get_indent(), ' ');
wid = emit_stmt_lval(scope, delayed_assign);
fprintf(vlog_out, " = ");
if (delay_type == IVL_ST_DELAYX) {
fprintf(vlog_out, "#(");
emit_scaled_delayx(scope, ivl_stmt_delay_expr(delay), 1);
} else {
fprintf(vlog_out, "@(");
emit_event(scope, delay);
}
fprintf(vlog_out, ") ");
emit_expr(scope, ivl_stmt_rval(assign), wid);
fprintf(vlog_out, ";");
emit_stmt_file_line(stmt);
fprintf(vlog_out, "\n");
return 1;
}