From bbf9bf3f0cfc7f0e4a81513b179443b205026ac9 Mon Sep 17 00:00:00 2001
From: Aadi Desai <21363892+supleed2@users.noreply.github.com>
Date: Tue, 30 May 2023 13:49:23 +0100
Subject: [PATCH] Further adjust bit offsets, improve accuracy from 1.34601 to
 0.455326

---
 cordic.sv  |  2 +-
 saw2sin.sv | 11 ++++++++---
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/cordic.sv b/cordic.sv
index e3629cd..1c39097 100644
--- a/cordic.sv
+++ b/cordic.sv
@@ -62,7 +62,7 @@ end
 /* verilator lint_on ALWCOMBORDER */
 
 always_comb
-  if (i_qph > 16'd65508)   o_sin = 16'hFFFF;
+  if (i_qph > 16'd65508)   o_sin = 16'hFFFE;
   else if (i_qph < 16'd32) o_sin = i_qph + (i_qph >> 1);
   else                     o_sin = y[19][17:2];
 
diff --git a/saw2sin.sv b/saw2sin.sv
index c9e753b..c74347d 100644
--- a/saw2sin.sv
+++ b/saw2sin.sv
@@ -22,8 +22,13 @@ cordic cordic
 , .o_sin (qsin)
 );
 
-always_comb o_sin = invert
-  ? ~{1'b1, qsin[15:1]} + 1 // Invert
-  : {1'b1, qsin[15:1]};     // Normal
+logic [16:0] sin;
+always_comb sin = reverse
+  ? (invert ? ~{1'b1, qsin[15:0]}          // Reverse, Invert
+            : {1'b1, qsin[15:0]} + 17'd1)  // Reverse, Normal
+  : (invert ? ~{1'b1, qsin[15:0]} + 17'd2  // Normal, Invert
+            : {1'b1, qsin[15:0]} + 17'd0); // Normal, Normal
+
+always_comb o_sin = sin[16:1];
 
 endmodule