Add new iCE40 delay estimator and delay predictor

Signed-off-by: Clifford Wolf <clifford@clifford.at>

1 files changed, 129 insertions, 4 deletions

diff --git a/ice40/delay.cc b/ice40/delay.cc
index d63af5d1..342b7f0b 100644
--- a/ice40/delay.cc
+++ b/ice40/delay.cc
@@ -23,7 +23,7 @@
 
 NEXTPNR_NAMESPACE_BEGIN
 
-#define NUM_FUZZ_ROUTES 100000
+#define NUM_FUZZ_ROUTES 1000
 
 void ice40DelayFuzzerMain(Context *ctx)
 {
@@ -101,20 +101,145 @@ void ice40DelayFuzzerMain(Context *ctx)
     }
 }
 
+namespace {
+
+struct model_params_t {
+    int neighbourhood;
+
+    int model0_offset;
+    int model0_norm1;
+
+    int model1_offset;
+    int model1_norm1;
+    int model1_norm2;
+    int model1_norm3;
+
+    int model2_offset;
+    int model2_linear;
+    int model2_sqrt;
+
+    int delta_local;
+    int delta_lutffin;
+    int delta_sp4;
+    int delta_sp12;
+
+    static const model_params_t &get(ArchArgs args)
+    {
+        static const model_params_t model_hx8k = {
+            588, 129253, 8658,
+            118333, 23915, -73105, 57696,
+            -86797, 89, 3706,
+            -316, -575, -158, -296
+        };
+
+        static const model_params_t model_lp8k = {
+            867, 206236, 11043,
+            191910, 31074, -95972, 75739,
+            -309793, 30, 11056,
+            -474, -856, -363, -536
+        };
+
+        static const model_params_t model_up5k = {
+            1761, 305798, 16705,
+            296830, 24430, -40369, 33038,
+            -162662, 94, 4705,
+            -1099, -1761, -418, -838
+        };
+
+        if (args.type == ArchArgs::HX1K || args.type == ArchArgs::HX8K)
+            return model_hx8k;
+
+        if (args.type == ArchArgs::LP384 || args.type == ArchArgs::LP1K || args.type == ArchArgs::LP8K)
+            return model_lp8k;
+
+        if (args.type == ArchArgs::UP5K)
+            return model_up5k;
+
+        NPNR_ASSERT(0);
+    }
+};
+
+} // namespace
+
 delay_t Arch::estimateDelay(WireId src, WireId dst) const
 {
     NPNR_ASSERT(src != WireId());
     int x1 = chip_info->wire_data[src.index].x;
     int y1 = chip_info->wire_data[src.index].y;
+    int z1 = chip_info->wire_data[src.index].z;
+    int type = chip_info->wire_data[src.index].type;
 
     NPNR_ASSERT(dst != WireId());
     int x2 = chip_info->wire_data[dst.index].x;
     int y2 = chip_info->wire_data[dst.index].y;
+    int z2 = chip_info->wire_data[dst.index].z;
+
+    int dx = abs(x2 - x1);
+    int dy = abs(y2 - y1);
+
+    const model_params_t &p = model_params_t::get(args);
+    delay_t v = p.neighbourhood;
+
+    if (dx > 1 || dy > 1)
+        v = (p.model0_offset + p.model0_norm1 * (dx + dy)) / 128;
+
+    if (type == WireInfoPOD::WIRE_TYPE_LOCAL)
+        v += p.delta_local;
+
+    if (type == WireInfoPOD::WIRE_TYPE_LUTFF_IN || type == WireInfoPOD::WIRE_TYPE_LUTFF_IN_LUT)
+        v += (z1 == z2) ? p.delta_lutffin : 1000;
+
+    if (type == WireInfoPOD::WIRE_TYPE_SP4_V || type == WireInfoPOD::WIRE_TYPE_SP4_H)
+        v += p.delta_sp4;
+
+    if (type == WireInfoPOD::WIRE_TYPE_SP12_V || type == WireInfoPOD::WIRE_TYPE_SP12_H)
+        v += p.delta_sp12;
+
+    return v;
+}
+
+delay_t Arch::predictDelay(const NetInfo *net_info, const PortRef &sink) const
+{
+    const auto &driver = net_info->driver;
+    auto driver_loc = getBelLocation(driver.cell->bel);
+    auto sink_loc = getBelLocation(sink.cell->bel);
+
+    if (driver.port == id_cout) {
+        if (driver_loc.y == sink_loc.y)
+            return 0;
+        return 250;
+    }
+
+    int dx = abs(sink_loc.x - driver_loc.x);
+    int dy = abs(sink_loc.y - driver_loc.y);
+
+    const model_params_t &p = model_params_t::get(args);
+
+    if (dx <= 1 && dy <= 1)
+        return p.neighbourhood;
+
+    float norm1 = dx + dy;
+
+    float dx2 = dx * dx;
+    float dy2 = dy * dy;
+    float norm2 = sqrtf(dx2 + dy2);
+
+    float dx3 = dx2 * dx;
+    float dy3 = dy2 * dy;
+    float norm3 = powf(dx3 + dy3, 1.0/3.0);
+
+    // Model #1
+    float v = p.model1_offset;
+    v += p.model1_norm1 * norm1;
+    v += p.model1_norm2 * norm2;
+    v += p.model1_norm3 * norm3;
+    v /= 128;
 
-    int xd = x2 - x1, yd = y2 - y1;
-    int xscale = 120, yscale = 120, offset = 0;
+    // Model #2
+    v = p.model2_offset + p.model2_linear * v + p.model2_sqrt * sqrtf(v);
+    v /= 128;
 
-    return xscale * abs(xd) + yscale * abs(yd) + offset;
+    return v;
 }
 
 NEXTPNR_NAMESPACE_END