intel_alm: Add multiply signedness to cells

Quartus assumes unsigned multiplication by default, breaking signed
multiplies, so add an input signedness parameter to the MISTRAL_MUL*
cells to propagate to Quartus' <family>_mac cells.

1 files changed, 48 insertions, 3 deletions

diff --git a/techlibs/intel_alm/common/dsp_sim.v b/techlibs/intel_alm/common/dsp_sim.v
index 45fdebb3f..bdb6d18d5 100644
--- a/techlibs/intel_alm/common/dsp_sim.v
+++ b/techlibs/intel_alm/common/dsp_sim.v
@@ -1,38 +1,83 @@
 (* abc9_box *)
 module MISTRAL_MUL27X27(input [26:0] A, input [26:0] B, output [53:0] Y);
 
+parameter A_SIGNED = 1;
+parameter B_SIGNED = 1;
+
 // TODO: Cyclone 10 GX timings; the below are for Cyclone V
 specify
     (A *> Y) = 3732;
     (B *> Y) = 3928;
 endspecify
 
-assign Y = $signed(A) * $signed(B);
+wire [53:0] A_, B_;
+
+if (A_SIGNED)
+    assign A_ = $signed(A);
+else
+    assign A_ = $unsigned(A);
+
+if (B_SIGNED)
+    assign B_ = $signed(B);
+else
+    assign B_ = $unsigned(B);
+
+assign Y = A_ * B_;
 
 endmodule
 
 (* abc9_box *)
 module MISTRAL_MUL18X18(input [17:0] A, input [17:0] B, output [35:0] Y);
 
+parameter A_SIGNED = 1;
+parameter B_SIGNED = 1;
+
 // TODO: Cyclone 10 GX timings; the below are for Cyclone V
 specify
     (A *> Y) = 3180;
     (B *> Y) = 3982;
 endspecify
 
-assign Y = $signed(A) * $signed(B);
+wire [35:0] A_, B_;
+
+if (A_SIGNED)
+    assign A_ = $signed(A);
+else
+    assign A_ = $unsigned(A);
+
+if (B_SIGNED)
+    assign B_ = $signed(B);
+else
+    assign B_ = $unsigned(B);
+
+assign Y = A_ * B_;
 
 endmodule
 
 (* abc9_box *)
 module MISTRAL_MUL9X9(input [8:0] A, input [8:0] B, output [17:0] Y);
 
+parameter A_SIGNED = 1;
+parameter B_SIGNED = 1;
+
 // TODO: Cyclone 10 GX timings; the below are for Cyclone V
 specify
     (A *> Y) = 2818;
     (B *> Y) = 3051;
 endspecify
 
-assign Y = $signed(A) * $signed(B);
+wire [17:0] A_, B_;
+
+if (A_SIGNED)
+    assign A_ = $signed(A);
+else
+    assign A_ = $unsigned(A);
+
+if (B_SIGNED)
+    assign B_ = $signed(B);
+else
+    assign B_ = $unsigned(B);
+
+assign Y = A_ * B_;
 
 endmodule