From 9fa4bb8ba28c07ce865347e3957a3062528d949a Mon Sep 17 00:00:00 2001
From: Lofty <dan.ravensloft@gmail.com>
Date: Tue, 1 Jul 2025 09:57:43 +0100
Subject: [PATCH] Remove A passthrough inversion option

---
 himbaechel/uarch/gatemate/gatemate.h   |  3 +--
 himbaechel/uarch/gatemate/pack_mult.cc | 22 +++++++++-------------
 2 files changed, 10 insertions(+), 15 deletions(-)

diff --git a/himbaechel/uarch/gatemate/gatemate.h b/himbaechel/uarch/gatemate/gatemate.h
index e0cf4044..3114c329 100644
--- a/himbaechel/uarch/gatemate/gatemate.h
+++ b/himbaechel/uarch/gatemate/gatemate.h
@@ -43,13 +43,12 @@ struct ZeroDriver
 // Propagate A0 through OUT1 and A1 through OUT2; zero COUTX and POUTX.
 struct APassThroughCell
 {
-    APassThroughCell(CellInfo *lower, CellInfo *upper, IdString name, bool inverted);
+    APassThroughCell(CellInfo *lower, CellInfo *upper, IdString name);
 
     void clean_up(Context *ctx);
 
     CellInfo *lower;
     CellInfo *upper;
-    bool inverted;
 };
 
 // Propagate B0 through POUTY1 and B1 through COUTY1
diff --git a/himbaechel/uarch/gatemate/pack_mult.cc b/himbaechel/uarch/gatemate/pack_mult.cc
index 6a3a388a..916c0f20 100644
--- a/himbaechel/uarch/gatemate/pack_mult.cc
+++ b/himbaechel/uarch/gatemate/pack_mult.cc
@@ -48,8 +48,8 @@ ZeroDriver::ZeroDriver(CellInfo *lower, CellInfo *upper, IdString name) : lower{
     upper->params[id_C_O2] = Property(0b11, 2); // COMB2OUT -> OUT2
 }
 
-APassThroughCell::APassThroughCell(CellInfo *lower, CellInfo *upper, IdString name, bool inverted)
-        : lower{lower}, upper{upper}, inverted{inverted}
+APassThroughCell::APassThroughCell(CellInfo *lower, CellInfo *upper, IdString name)
+        : lower{lower}, upper{upper}
 {
     lower->params[id_INIT_L02] = Property(LUT_D0, 4);   // IN5
     lower->params[id_INIT_L03] = Property(LUT_ZERO, 4); // (unused)
@@ -80,30 +80,26 @@ void APassThroughCell::clean_up(Context *ctx)
 
     {
         bool net_is_gnd =
-                lower_net->name == ctx->idf("$PACKER_GND") || (inverted && lower_net->name == ctx->idf("$PACKER_VCC"));
+                lower_net->name == ctx->idf("$PACKER_GND");
         bool net_is_vcc =
-                lower_net->name == ctx->idf("$PACKER_VCC") || (inverted && lower_net->name == ctx->idf("$PACKER_GND"));
+                lower_net->name == ctx->idf("$PACKER_VCC");
         if (net_is_gnd || net_is_vcc) {
             lower->params[id_INIT_L02] = Property(LUT_ZERO, 4);
             lower->params[id_INIT_L11] = Property(LUT_ZERO, 4);
             lower->params[id_INIT_L20] = Property(net_is_vcc ? LUT_ONE : LUT_ZERO, 4);
             lower->disconnectPort(id_IN1);
-        } else if (inverted) {
-            lower->params[id_INIT_L02] = Property(LUT_INV_D0, 4);
         }
     }
 
     {
         bool net_is_gnd =
-                upper_net->name == ctx->idf("$PACKER_GND") || (inverted && upper_net->name == ctx->idf("$PACKER_VCC"));
+                upper_net->name == ctx->idf("$PACKER_GND");
         bool net_is_vcc =
-                upper_net->name == ctx->idf("$PACKER_VCC") || (inverted && upper_net->name == ctx->idf("$PACKER_GND"));
+                upper_net->name == ctx->idf("$PACKER_VCC");
         if (net_is_gnd || net_is_vcc) {
             upper->params[id_INIT_L00] = Property(LUT_ZERO, 4);
             upper->params[id_INIT_L10] = Property(net_is_vcc ? LUT_ONE : LUT_ZERO, 4);
             upper->disconnectPort(id_IN1);
-        } else if (inverted) {
-            upper->params[id_INIT_L00] = Property(LUT_INV_D0, 4);
         }
     }
 }
@@ -304,10 +300,10 @@ void GateMatePacker::pack_mult()
         return ZeroDriver{zero_lower, zero_upper, name};
     };
 
-    auto create_a_passthru = [&](IdString name, bool inverted) {
+    auto create_a_passthru = [&](IdString name) {
         auto *a_passthru_lower = create_cell_ptr(id_CPE_HALF_L, ctx->idf("%s$a_passthru_lower", name.c_str(ctx)));
         auto *a_passthru_upper = create_cell_ptr(id_CPE_HALF_U, ctx->idf("%s$a_passthru_upper", name.c_str(ctx)));
-        return APassThroughCell{a_passthru_lower, a_passthru_upper, name, inverted};
+        return APassThroughCell{a_passthru_lower, a_passthru_upper, name};
     };
 
     auto create_mult_col = [&](IdString name, int a_width, bool is_even_x, bool carry_enable_cinx,
@@ -391,7 +387,7 @@ void GateMatePacker::pack_mult()
         // Step 1: instantiate all the CPEs.
         m.zero = create_zero_driver(ctx->idf("%s$col0", mult->name.c_str(ctx)));
         for (int a = 0; a < a_width / 2; a++)
-            m.a_passthrus.push_back(create_a_passthru(ctx->idf("%s$col0$row%d", mult->name.c_str(ctx), a), false));
+            m.a_passthrus.push_back(create_a_passthru(ctx->idf("%s$col0$row%d", mult->name.c_str(ctx), a)));
         for (int b = 0; b < b_width / 2; b++)
             m.cols.push_back(create_mult_col(ctx->idf("%s$col%d", mult->name.c_str(ctx), b + 1), a_width, b % 2 == 0,
                                              b == 2 /* ??? */, b > 0 /* ??? */));