From d9a10a7d07eeda6b4493e8799dc10eb95e02ea75 Mon Sep 17 00:00:00 2001
From: Kistaro Windrider <kistaro@gmail.com>
Date: Sun, 8 Jun 2025 16:14:18 -0700
Subject: [PATCH] fastest sqrt version, fix percentage

---
 magnitest.p8 | 26 ++++++++++++++++++++++----
 profiling.p8 |  5 +++++
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/magnitest.p8 b/magnitest.p8
index f7cbbf6..3a3c88f 100644
--- a/magnitest.p8
+++ b/magnitest.p8
@@ -22,6 +22,16 @@ function bbs28999algopt(dx, dy)
   return (n*n + 1)^0.5 * d
 end
 
+-- profiler says 54 cycles
+-- 26 lua, 28 system
+function bbs28999algopt2(dx, dy)
+  local d,n=abs(dx),abs(dy)
+  if (d<n) d,n=n,d
+  n/=d
+  return sqrt(n*n + 1) * d
+end
+
+
 -- profiler says 18 cycles
 -- 18 lua, 0 system
 function trigalg(dx, dy)
@@ -37,6 +47,7 @@ function _init()
  tresult=0
  bresult=0
  delta=0
+ dp=0
 end
 
 function _update60()
@@ -45,25 +56,30 @@ function _update60()
  if (btn(2)) gdy -= acc
  if (btn(3)) gdy += acc
  if (btn(4) and btn(5)) gdx,gdy=0,0
+ gdx=mid(-16000,16000,gdx)
+ gdy=mid(-16000,16000,gdy)
 
  if btn() == 0 or btn(4) then
   acc = 1
  elseif btn(5) then
-  acc *= 1.1
+  acc *= 1.05
  else
   acc *= 1.02
  end
+ if (acc > 1024) acc=1024
 
  local a,b=abs(gdx),abs(gdy)
  if (b>a) a,b=b,a
  magnitude = 1
- while magnitude*64 < a do
+ while magnitude < a/64 do
   magnitude *= 2
  end
 
- bresult=bbs28999algopt(gdx,gdy)
+ bresult=bbs28999algopt2(gdx,gdy)
  tresult=trigalg(gdx,gdy)
  delta=tresult-bresult
+ dp=(2*abs(delta)/abs(abs(bresult)+abs(tresult)))*100
+ if (delta == 0) dp=0
 end
 
 cols = {
@@ -81,11 +97,13 @@ cols = {
 
 function _draw()
  cls()
+ camera()
+ print("x: "..tostr(gdx).."  y: "..tostr(gdy).."\nbase: "..tostr(bresult).."\ntrig: "..tostr(tresult).."\n\ndiff: "..tostr(delta).."\n   %:"..tostr(dp),0,0,13)
+ print("⬆️⬇️⬅️➡️:move  ❎:fast 🅾️:slow\n❎+🅾️:reset position",0,117,12)
  camera(-63,-63)
  line(0,0,gdx/magnitude,gdy/magnitude,cols[magnitude] or 2)
  rectfill(0,0,gdx/magnitude,0,5)
  rectfill(0,0,0,gdy/magnitude,5)
- print("x: "..tostr(gdx).."  y: "..tostr(gdy).."\nbase: "..tostr(bresult).."\ntrig: "..tostr(tresult).."\n\ndiff: "..tostr(delta),-63,-63,13)
 end
 
 __gfx__
diff --git a/profiling.p8 b/profiling.p8
index 5d5bd6e..9c33151 100644
--- a/profiling.p8
+++ b/profiling.p8
@@ -352,6 +352,11 @@ end,function(dx, dy)
   if (d<n) d,n=n,d
   n/=d
   return (n*n + 1)^0.5 * d
+end,function(dx,dy)
+  local d,n=abs(dx),abs(dy)
+  if (d<n) d,n=n,d
+  n/=d
+  return sqrt(n*n + 1) * d
 end,function(dx,dy)
  local s = sin(atan2(dx,dy))
  if (s==0) return abs(dx)