From 7e5ca79d9a4bd419a3a004f7c96a612c9e41cee7 Mon Sep 17 00:00:00 2001
From: Brooke Vibber <bvibber@pobox.com>
Date: Sat, 4 Jan 2025 14:25:25 -0800
Subject: [PATCH] move total_ms, total_pixels out of zero page

this frees up 12 bytes of zero page space and costs no measurable
time as these variables are not in the hot path and there was only
a tiny bit different.
---
 mandel.s | 37 +++++++++++++++++++++++++------------
 1 file changed, 25 insertions(+), 12 deletions(-)

diff --git a/mandel.s b/mandel.s
index 526953a..317e3b1 100644
--- a/mandel.s
+++ b/mandel.s
@@ -33,8 +33,7 @@ chroma_ticks    = $bd ; u8
 count_frames    = $be ; u8
 count_pixels    = $bf ; u8
 
-total_pixels    = $c0 ; float48
-total_ms        = $c6 ; float48
+; free space c0-cb
 temp            = $cc ; u16
 temp2           = $ce ; u16
 
@@ -63,6 +62,7 @@ FADD   = $DA66 ; ADDITION       (FR0 += FR1)
 FSUB   = $DA60 ; SUBTRACTION    (FR0 -= FR1)
 FMUL   = $DADB ; MULTIPLICATION (FR0 *= FR1)
 FDIV   = $DB28 ; DIVISION       (FR0 /= FR1)
+ZFR0   = $DA44 ; clear FR0
 ZF1    = $DA46 ; CLEAR ZERO PAGE FLOATING POINT NUMBER (XX)
 FLD0R  = $DD89 ; LOAD FR0 WITH FLOATING POINT NUMBER (YYXX)
 FLD1R  = $DD98 ; LOAD FR1 WITH FLOATING POINT NUMBER (YYXX)
@@ -203,6 +203,16 @@ ms_per_frame: ; float48 16.66666667
     .byte $66
     .byte $67
 
+total_pixels: ; float48
+    .repeat 6
+        .byte 0
+    .endrepeat
+
+total_ms: ; float48
+    .repeat 6
+        .byte 0
+    .endrepeat
+
 display_list_start:
     ; 24 lines overscan
     .repeat 3
@@ -1565,10 +1575,13 @@ main_loop:
     sta count_pixels
 
     ; total_ms = 0.0; total_pixels = 0.0
-    ldx #total_ms
-    jsr ZF1
-    ldx #total_pixels
-    jsr ZF1
+    jsr ZFR0
+    ldx #.lobyte(total_ms)
+    ldy #.hibyte(total_ms)
+    jsr FST0R
+    ldx #.lobyte(total_pixels)
+    ldy #.hibyte(total_pixels)
+    jsr FST0R
 
     jsr clear_screen
     jsr status_bar
@@ -1691,19 +1704,19 @@ update_status:
     jsr FMUL
 
     ; FR0 += total_ms
-    ldx #total_ms
-    ldy #0
+    ldx #.lobyte(total_ms)
+    ldy #.hibyte(total_ms)
     jsr FLD1R
     jsr FADD
 
     ; total_ms = FR0
-    ldx #total_ms
-    ldy #0
+    ldx #.lobyte(total_ms)
+    ldy #.hibyte(total_ms)
     jsr FST0R
 
     ; FR0 /= total_pixels
-    ldx #total_pixels
-    ldy #0
+    ldx #.lobyte(total_pixels)
+    ldy #.hibyte(total_pixels)
     jsr FLD1R
     jsr FDIV