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More fixes in ast expression sign/width handling

This commit is contained in:
Clifford Wolf 2013-07-09 23:41:28 +02:00
parent 618b2ac994
commit 5dab327b30
2 changed files with 22 additions and 21 deletions
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17
frontends/ast/genrtlil.cc
View File

@ -530,7 +530,7 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint)
break;
case AST_TO_UNSIGNED:
children.at(0)->detectSignWidthWorker(width_hint, sign_hint);
children.at(0)->detectSignWidthWorker(width_hint, dummy_sign_hint);
sign_hint = false;
break;
@ -593,8 +593,8 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint)
case AST_LOGIC_AND:
case AST_LOGIC_OR:
case AST_LOGIC_NOT:
for (auto child : children)
child->detectSignWidthWorker(width_hint, sign_hint);
width_hint = std::max(width_hint, 1);
sign_hint = false;
break;
case AST_TERNARY:
@ -835,7 +835,7 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
// just pass thru the signal. the parent will evaluated the is_signed property and inperpret the SigSpec accordingly
case AST_TO_SIGNED:
case AST_TO_UNSIGNED: {
RTLIL::SigSpec sig = children[0]->genRTLIL(width_hint, sign_hint);
RTLIL::SigSpec sig = children[0]->genRTLIL();
is_signed = type == AST_TO_SIGNED;
return sig;
}
@ -889,6 +889,8 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
if (0) { case AST_BIT_XOR: type_name = "$xor"; }
if (0) { case AST_BIT_XNOR: type_name = "$xnor"; }
{
if (width_hint < 0)
detectSignWidth(width_hint, sign_hint);
RTLIL::SigSpec left = children[0]->genRTLIL(width_hint, sign_hint);
RTLIL::SigSpec right = children[1]->genRTLIL(width_hint, sign_hint);
int width = std::max(left.width, right.width);
@ -965,12 +967,9 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
if (width > width_hint && width_hint > 0)
width = width_hint;
if (width < width_hint) {
if (type == AST_ADD || type == AST_SUB) {
if (type == AST_ADD || type == AST_SUB)
width++;
if (width < width_hint && children[0]->is_signed != children[1]->is_signed)
width++;
}
if (type == AST_SUB && !children[0]->is_signed && !children[1]->is_signed)
if (type == AST_SUB && (!children[0]->is_signed || !children[1]->is_signed))
width = width_hint;
if (type == AST_MUL)
width = std::min(left.width + right.width, width_hint);

26
tests/simple/vloghammer.v
View File

@ -27,19 +27,21 @@ module test04(a, y);
assign y = ~(a - 1'b0);
endmodule
module test05(a, y);
input a;
output y;
assign y = 12345 >> {a, 32'd0};
endmodule
// .. this test triggers a bug in xilinx isim.
// module test05(a, y);
// input a;
// output y;
// assign y = 12345 >> {a, 32'd0};
// endmodule
module test06(a, b, c, y);
input signed [3:0] a;
input signed [1:0] b;
input signed [1:0] c;
output [5:0] y;
assign y = (a >> b) >>> c;
endmodule
// .. this test triggers a bug in icarus verilog.
// module test06(a, b, c, y);
// input signed [3:0] a;
// input signed [1:0] b;
// input signed [1:0] c;
// output [5:0] y;
// assign y = (a >> b) >>> c;
// endmodule
module test07(a, b, y);
input signed [1:0] a;