From 695f589d1bf75e17d676aab4f53c4dcf187cf554 Mon Sep 17 00:00:00 2001
From: Rob McMullen <feedback@playermissile.com>
Date: Fri, 30 Jun 2017 21:56:27 -0700
Subject: [PATCH] backingstore: mini optimization using smc instead of
 recomputing the column

---
 backingstore-3x11.s |  11 ++++++++---
 multitest.dsk       | Bin 143360 -> 143360 bytes
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/backingstore-3x11.s b/backingstore-3x11.s
index 7dbacbc..0db9cd6 100644
--- a/backingstore-3x11.s
+++ b/backingstore-3x11.s
@@ -51,6 +51,12 @@ savebg_3x11
     sta (bgstore),y
     iny
 
+    ; set up smc for hires column, because the starting column doesn't change
+    ; when moving to the next row
+    ldx PARAM0
+    lda DIV7_1,x
+    sta savebg_3x11_smc1+1
+
 savebg_3x11_line
     ; save a line, starting from the topmost and working down
     ldx SCRATCH0  ; Calculate Y line
@@ -64,9 +70,8 @@ savebg_3x11_line
     sta savebg_3x11_col1+1
     sta savebg_3x11_col2+1
 
-    ldx PARAM0                              ; Compute hires column
-    lda DIV7_1,x
-    tax
+savebg_3x11_smc1
+    ldx #$ff
 
 savebg_3x11_col0
     lda $2000,x
diff --git a/multitest.dsk b/multitest.dsk
index 41b55aefecff2ed1a1d62f459314037dfa8d2943..947b04d14648a0626445bf1e62cf6eb972880fcd 100644
GIT binary patch
delta 247
zcmZp8z|ru4W5X6k#u<}0@QY49#rPh|I?n`SU19cvidnGCg|IfiW;wzIX1)TGlAE^(
z_^=E1Dwp+YmF;CI>6I?)RVwS%oXjinev%}oW$eUXCsvjMiKT2Hg1uD|NG)UA8&c5g
zSh`GdZ%a|HOKGonX>U*|NVjuouUBbrVCka&lkFrWWlkk5V+Sc|EbZ+m?d=CEX(;V&
zFYWCsoy;d8J9&bn2;+~*T#{14_e*=9mG-^`E4f$N`?R$8&17>)xyc_SxtL_inxxvK
K7?(*gi2(o<h-rHO

delta 253
zcmZp8z|ru4W5X6k#wn9G@QY49#rPh|I?n`SU19cvidnGCg|IfiW;wzIX1)TGlAE^(
z_^|V;mF;CI=@l>Ql`HF2oh&Hve&Pa_Ns^p;krRKNSXl}rma>5e_Et$CwM=qvOHr>w
zX|H=}uU{!hqkU<wTWPQF<ZF_0vZ@n~B`jkHsi-aOZ7J>T2CJwk?QJgY?V4OBX{7fB
qx1qO7dmokdz65KzRoeTowD$$jPz^STvR?VJ-X^IwDaK_|Okx0@&~j1$