diff options
Diffstat (limited to 'frontends/ast')
| -rw-r--r-- | frontends/ast/genrtlil.cc | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/frontends/ast/genrtlil.cc b/frontends/ast/genrtlil.cc index 2788a850f..4c25287ad 100644 --- a/frontends/ast/genrtlil.cc +++ b/frontends/ast/genrtlil.cc @@ -1531,13 +1531,20 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint) // changing the size of signal can be done directly using RTLIL::SigSpec case AST_CAST_SIZE: { RTLIL::SigSpec size = children[0]->genRTLIL(); - RTLIL::SigSpec sig = children[1]->genRTLIL(); if (!size.is_fully_const()) log_file_error(filename, location.first_line, "Static cast with non constant expression!\n"); int width = size.as_int(); if (width <= 0) log_file_error(filename, location.first_line, "Static cast with zero or negative size!\n"); - sig.extend_u0(width, sign_hint); + // determine the *signedness* of the expression + int sub_width_hint = -1; + bool sub_sign_hint = true; + children[1]->detectSignWidth(sub_width_hint, sub_sign_hint); + // generate the signal given the *cast's* size and the + // *expression's* signedness + RTLIL::SigSpec sig = children[1]->genWidthRTLIL(width, sub_sign_hint); + // context may effect this node's signedness, but not that of the + // casted expression is_signed = sign_hint; return sig; } |