luke
/
iverilog
mirror of https://github.com/steveicarus/iverilog.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Iterate static arrays $left to $right in foreach loops 

foreach loops are supposed to iterate arrays $left to $right. E.g. `reg
x[3:0]` should be iterated from 3 to 0 and `y[1:4]` from 1 to 4.

The current implementation iterates them from $low to $high. Modify this to
either count up or down depending on whether $left or $right is the larger
of the two values.

Note that the same applies for dynamic arrays. But since for dynamic arrays
$left is always 0 and $right is always $high they always count up and we do
not need to differentiate between two different cases.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
This commit is contained in:
Lars-Peter Clausen 2023-03-05 08:58:12 -08:00
parent 0144168723
commit e19d077d44
1 changed files with 15 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
elaborate.cc
View File

@ -5276,7 +5276,7 @@ static void find_property_in_class(const LineInfo&loc, const NetScope*scope, per
/*
* The foreach statement can be written as a for statement like so:
*
* for (<idx> = $low(<array>) ; <idx> <= $high(<array>) ; <idx> += 1)
* for (<idx> = $left(<array>) ; <idx> {<,>}= $right(<array>) ; <idx> {+,-}= 1)
* <statement_>
*
* The <idx> variable is already known to be in the containing named
@ -5386,6 +5386,9 @@ NetProc* PForeach::elaborate(Design*des, NetScope*scope) const
NetESignal*idx_exp = new NetESignal(idx_sig);
idx_exp->set_line(*this);
// This is a dynamic array or queue where $low is $left and $high is
// $right. It will always count up.
// Make an initialization expression for the index.
NetESFunc*init_expr = new NetESFunc("$low", &netvector_t::atom2s32, 1);
init_expr->set_line(*this);
@ -5458,36 +5461,33 @@ NetProc* PForeach::elaborate_static_array_(Design*des, NetScope*scope,
// Get the $high and $low constant values for this slice
// of the array.
NetEConst*hig_expr = make_const_val_s(idx_range.get_msb());
NetEConst*low_expr = make_const_val_s(idx_range.get_lsb());
if (idx_range.get_msb() < idx_range.get_lsb()) {
NetEConst*tmp = hig_expr;
hig_expr = low_expr;
low_expr = tmp;
}
NetEConst*left_expr = make_const_val_s(idx_range.get_msb());
NetEConst*right_expr = make_const_val_s(idx_range.get_lsb());
hig_expr->set_line(*this);
low_expr->set_line(*this);
bool up = idx_range.get_msb() < idx_range.get_lsb();
left_expr->set_line(*this);
right_expr->set_line(*this);
pform_name_t idx_name;
idx_name.push_back(name_component_t(index_vars_[idx_idx]));
NetNet*idx_sig = des->find_signal(scope, idx_name);
ivl_assert(*this, idx_sig);
// Make the condition expression <idx> <= $high(slice)
// Make the condition expression <idx> {<,>}= $right(slice)
NetESignal*idx_expr = new NetESignal(idx_sig);
idx_expr->set_line(*this);
NetEBComp*cond_expr = new NetEBComp('L', idx_expr, hig_expr);
NetEBComp*cond_expr = new NetEBComp(up ? 'L' : 'G', idx_expr, right_expr);
cond_expr->set_line(*this);
// Make the step statement: <idx> += 1
// Make the step statement: <idx> {+,-}= 1
NetAssign_*idx_lv = new NetAssign_(idx_sig);
NetEConst*step_val = make_const_val_s(1);
NetAssign*step = new NetAssign(idx_lv, '+', step_val);
NetAssign*step = new NetAssign(idx_lv, up ? '+' : '-', step_val);
step->set_line(*this);
stmt = new NetForLoop(idx_sig, low_expr, cond_expr, sub, step);
stmt = new NetForLoop(idx_sig, left_expr, cond_expr, sub, step);
stmt->set_line(*this);
sub = stmt;