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vastly improved lazy synapse handshakes

This commit is contained in:
alexmadison 2022-03-31 12:44:00 +02:00
parent cd5d41d7f8
commit 2e4cdd5029
1 changed files with 156 additions and 193 deletions
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71
dataflow_neuro/coders.act
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@ -190,89 +190,52 @@ namespace tmpl {
// Acknowledge pull down time
// Pull DOWNs on the reqB lines by synapses (easier to invert).
bool _out_reqsB[Nx], _out_acksB[Nx]; // The vertical output ack lines from each syn.
PULLDOWN2_X4 req_pulldowns[Nx*Ny];
// Pull DOWNs on the ackB lines by synapses (easier to invert).
bool _out_acksB[Nx]; // The vertical output ack lines from each syn.
PULLDOWN2_X4 ack_pulldowns[Nx*Ny];
pint index;
(i:Nx:
(j:Ny:
index = i + Nx*j;
req_pulldowns[index].a = out[index].a;
req_pulldowns[index].b = _out_acksB[i];
req_pulldowns[index].y = _out_reqsB[i];
req_pulldowns[index].vss = supply.vss;
req_pulldowns[index].vdd = supply.vdd;
ack_pulldowns[index].a = out[index].a;
ack_pulldowns[index].b = d_dr_x.out[i];
ack_pulldowns[index].y = _out_acksB[i];
ack_pulldowns[index].vss = supply.vss;
ack_pulldowns[index].vdd = supply.vdd;
)
)
// ReqB keep cells
KEEP_X1 req_keeps[Nx];
(i:Nx:
req_keeps[i].y = _out_reqsB[i];
req_keeps[i].vdd = supply.vdd;
req_keeps[i].vss = supply.vss;
)
// req-ack buffers
// Delay needed here, since otherwise the pull up of reqB happens too quickly.
// Means that the pull up may start fighting the synapse,
// since the synapse has not yet retracted its ack.
// Also there is the possibility, if really fast, that the line pull up block
// doesn't yet see that the input is valid, and starts pulling up.
// In any case, this delay is important.
sigbuf<Ny> req_bufs[Nx];
delay_chain<N_dly> ack_delays[Nx];
(i:Nx:
ack_delays[i].in = _out_reqsB[i];
ack_delays[i].supply = supply;
// req_bufs[i].in = _out_reqsB[i];
req_bufs[i].in = ack_delays[i].out;
req_bufs[i].out[0] = _out_acksB[i]; // DANGER DANGER
req_bufs[i].supply = supply;
)
// Line end pull UPs (triggered once synapse reqs removed)
OR2_X1 pu_ORs[Nx];
// Line end pull UPs (triggered once reqs removed)
PULLUP_X4 pu[Nx]; // TODO probably replace this with variable strength PU
AND2_X1 pu_ANDs[Nx];
(i:Nx:
pu_ORs[i].a = _out_acksB[i];
pu_ORs[i].b = d_dr_x.out[i];
pu_ORs[i].vdd = supply.vdd;
pu_ORs[i].vss = supply.vss;
pu_ANDs[i].a = pu_ORs[i].y;
pu_ANDs[i].a = d_dr_x.out[i];
pu_ANDs[i].b = reset_B; // TODO buffer
pu_ANDs[i].vdd = supply.vdd;
pu_ANDs[i].vss = supply.vss;
pu[i].a = pu_ANDs[i].y;
pu[i].y = _out_reqsB[i];
pu[i].y = _out_acksB[i];
pu[i].vdd = supply.vdd;
pu[i].vss = supply.vss;
)
// ORtree from all output reqs, back to the buffer ack.
// ORtree from all output acks, back to the buffer ack.
// This is instead of the ack that came from the delayed validity trees,
// in decoder_2d_dly.
ortree<Nx> _ortree(.out = addr_buf.out.a, .supply = supply);
INV_X1 out_req_invs[Nx];
INV_X1 out_ack_invs[Nx];
(i:Nx:
out_req_invs[i].a = _out_reqsB[i];
out_req_invs[i].vdd = supply.vdd;
out_req_invs[i].vss = supply.vss;
out_ack_invs[i].a = _out_acksB[i];
out_ack_invs[i].vdd = supply.vdd;
out_ack_invs[i].vss = supply.vss;
_ortree.in[i] = out_req_invs[i].y;
_ortree.in[i] = out_ack_invs[i].y;
)
}
/*
* Build an arbiter_handshake tree.
*/