diff --git a/readme.md b/readme.md
index f297d60..d60644c 100644
--- a/readme.md
+++ b/readme.md
@@ -27,7 +27,7 @@ The 16-bit signed integer multiplication takes two 16-bit inputs and emits one 3
 * when expanded RAM is available as on 130XE, a 64KB 8-bit multiplication table accelerates the remaining multiplications
 * without expanded RAM, a table of half-squares is used to implement the algorithm from https://everything2.com/title/Fast+6502+multiplication
 
-The mandelbrot calculations are done using 4.12-precision fixed point numbers. It may be possible to squish this down to 3.13.
+The mandelbrot calculations are done using 4.12-precision fixed point numbers with 8.24-precision intermediates. It may be possible to squish this down to 3.13/6.26.
 
 Iterations are capped at 255.
 
@@ -47,4 +47,4 @@ Currently produces a `.xex` executable, which can be booted up in common Atari e
 
 ## Todo
 
-See ideas in `todo.md`.
\ No newline at end of file
+See ideas in `todo.md`.
diff --git a/todo.md b/todo.md
index 29217cd..284d653 100644
--- a/todo.md
+++ b/todo.md
@@ -3,13 +3,11 @@ things to try:
 * skip add on the top-byte multiply in sqr8/mul8
   * should save a few cycles, suggestion by jamey
 
-* perform the zx_next = zx^s + cx in 32-bit space, before rounding
-  * should improve precision on max zoom, might cost a few cycles
-
 * patch the entire expanded-ram imul8xe on top of imul8 to avoid the 3-cycle thunk penalty :D
 
 * try 3.13 fixed point instead of 4.12 for more precision
   * can we get away without the extra bit?
+  * since exit compare space would be 6.26 i think so
 
 * y-axis mirror optimization