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Added the obvious optimizations to alumacc $macc generator

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This commit is contained in:
Clifford Wolf 2014-09-15 12:22:03 +02:00
parent fcbda07411
commit b470c480e9
2 changed files with 61 additions and 0 deletions
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60
kernel/macc.h
View file

@ -34,6 +34,66 @@ struct Macc
std::vector<port_t> ports; std::vector<port_t> ports;
RTLIL::SigSpec bit_ports; RTLIL::SigSpec bit_ports;
void optimize(int width)
{
std::vector<port_t> new_ports;
RTLIL::SigSpec new_bit_ports;
RTLIL::Const off(0, width);
for (auto &port : ports)
{
if (SIZE(port.in_a) == 0 && SIZE(port.in_b) == 0)
continue;
if (SIZE(port.in_a) == 1 && SIZE(port.in_b) == 0 && !port.is_signed && !port.do_subtract) {
bit_ports.append(port.in_a);
continue;
}
if (port.in_a.is_fully_const() && port.in_b.is_fully_const()) {
RTLIL::Const v = port.in_a.as_const();
if (SIZE(port.in_b))
v = const_mul(v, port.in_b.as_const(), port.is_signed, port.is_signed, width);
if (port.do_subtract)
off = const_sub(off, v, port.is_signed, port.is_signed, width);
else
off = const_add(off, v, port.is_signed, port.is_signed, width);
continue;
}
if (port.is_signed) {
while (SIZE(port.in_a) > 1 && port.in_a[SIZE(port.in_a)-1] == port.in_a[SIZE(port.in_a)-2])
port.in_a.remove(SIZE(port.in_a)-1);
while (SIZE(port.in_b) > 1 && port.in_b[SIZE(port.in_b)-1] == port.in_b[SIZE(port.in_b)-2])
port.in_b.remove(SIZE(port.in_b)-1);
} else {
while (SIZE(port.in_a) > 1 && port.in_a[SIZE(port.in_a)-1] == RTLIL::S0)
port.in_a.remove(SIZE(port.in_a)-1);
while (SIZE(port.in_b) > 1 && port.in_b[SIZE(port.in_b)-1] == RTLIL::S0)
port.in_b.remove(SIZE(port.in_b)-1);
}
new_ports.push_back(port);
}
for (auto &bit : bit_ports)
if (bit == RTLIL::S1)
off = const_add(off, RTLIL::Const(1, width), false, false, width);
else if (bit != RTLIL::S0)
new_bit_ports.append(bit);
if (off.as_bool()) {
port_t port;
port.in_a = off;
port.is_signed = false;
port.do_subtract = false;
new_ports.push_back(port);
}
new_ports.swap(ports);
bit_ports = new_bit_ports;
}
void from_cell(RTLIL::Cell *cell) void from_cell(RTLIL::Cell *cell)
{ {
RTLIL::SigSpec port_a = cell->getPort("\\A"); RTLIL::SigSpec port_a = cell->getPort("\\A");

1
passes/techmap/alumacc.cc
View file

@ -317,6 +317,7 @@ struct AlumaccWorker
log(" creating $macc cell for %s: %s\n", log_id(n->cell), log_id(cell)); log(" creating $macc cell for %s: %s\n", log_id(n->cell), log_id(cell));
n->macc.optimize(SIZE(n->y));
n->macc.to_cell(cell); n->macc.to_cell(cell);
cell->setPort("\\Y", n->y); cell->setPort("\\Y", n->y);
cell->fixup_parameters(); cell->fixup_parameters();