reduce LHS for RSQRT by a factor of fract_width and

"sensible answers" start appearing from the div/sqrt/rsqrt algorithm

diff --git a/src/ieee754/div_rem_sqrt_rsqrt/core.py b/src/ieee754/div_rem_sqrt_rsqrt/core.py
index adc68ffcc5e300d1871df36909b69ac5c971d9a8..2e5240383d7a65d5f01c248ec6851178d6368218 100644 (file)
--- a/src/ieee754/div_rem_sqrt_rsqrt/core.py
+++ b/src/ieee754/div_rem_sqrt_rsqrt/core.py
@@ -249,7 +249,7 @@ class DivPipeCoreSetupStage(Elaboratable):
                 self.i.divisor_radicand << (self.core_config.fract_width * 2))
         with m.Else():  # DivPipeCoreOperation.RSqrtRem
             m.d.comb += self.o.compare_lhs.eq(
-                1 << (self.core_config.fract_width * 3))
+                1 << (self.core_config.fract_width * 2))
 
         m.d.comb += self.o.compare_rhs.eq(0)
         m.d.comb += self.o.operation.eq(self.i.operation)