From b56dc1e98bfeb3c18c4f90df0e0d19fbe5362cde Mon Sep 17 00:00:00 2001
From: Brooke Vibber <bvibber@pobox.com>
Date: Mon, 30 Dec 2024 20:38:33 -0800
Subject: [PATCH] notes

---
 mandel.s | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/mandel.s b/mandel.s
index b88105b..fc30532 100644
--- a/mandel.s
+++ b/mandel.s
@@ -417,19 +417,20 @@ viewport_oy:
     neg 4, arg
 .endmacro
 
-; 23 * shift
+; 11-27 + 23 * shift cycles
+; 103-119 cycles for shift=4
 .macro shift_round_16 arg, shift
     .repeat shift
         shl32 arg ; 23 cycles
     .endrepeat
-    round16 arg
+    round16 arg ; 11-27 cycles
 .endmacro
 
 .macro imul16_round dest, arg1, arg2, shift
     copy16 FR0, arg1  ; 12 cyc
     copy16 FR1, arg2  ; 12 cyc
     jsr imul16_func   ; ? cyc
-    shift_round_16 FR2, shift
+    shift_round_16 FR2, shift ; 103-119 cycles for shift=4
     copy16 dest, FR2 + 2  ; 12 cyc
 .endmacro
 
@@ -437,7 +438,7 @@ viewport_oy:
     ;imul16_round dest, arg, arg, shift
     copy16 FR0, arg   ; 12 cyc
     jsr sqr16_func      ; ? cyc
-    shift_round_16 FR2, shift
+    shift_round_16 FR2, shift ; 103-119 cycles for shift=4
     copy16 dest, FR2 + 2  ; 12 cyc
 .endmacro