From 5d38d8c6ec65fd53d8dfc562260bfc486b25eda9 Mon Sep 17 00:00:00 2001
From: jespergravgaard <jesper@balmangravgaard.dk>
Date: Thu, 18 Oct 2018 23:28:59 +0200
Subject: [PATCH] Changed rotate to use 8-bit sine and 8x8 bit multiplication.

---
 src/main/fragment/vwsz1=vbsaa_plus_vbuc1.asm | 15 +++++++++++++++
 src/main/fragment/vwsz1=vwsz1_rol_1.asm      |  2 ++
 src/main/fragment/vwsz1=vwsz1_rol_2.asm      |  4 ++++
 src/main/fragment/vwsz1=vwsz2_rol_1.asm      |  6 ++++++
 src/test/kc/examples/rotate/rotate.kc        | 16 ++++++++--------
 5 files changed, 35 insertions(+), 8 deletions(-)
 create mode 100644 src/main/fragment/vwsz1=vbsaa_plus_vbuc1.asm
 create mode 100644 src/main/fragment/vwsz1=vwsz1_rol_1.asm
 create mode 100644 src/main/fragment/vwsz1=vwsz1_rol_2.asm
 create mode 100644 src/main/fragment/vwsz1=vwsz2_rol_1.asm

diff --git a/src/main/fragment/vwsz1=vbsaa_plus_vbuc1.asm b/src/main/fragment/vwsz1=vbsaa_plus_vbuc1.asm
new file mode 100644
index 000000000..126b62c53
--- /dev/null
+++ b/src/main/fragment/vwsz1=vbsaa_plus_vbuc1.asm
@@ -0,0 +1,15 @@
+sta {z1}
+// sign-extend the byte
+ora #$7f
+bmi !+
+lda #0
+!:
+sta {z1}+1
+// add the constant
+lda {z1}
+clc
+adc #{c1}
+sta {z1}
+lda {z1}+1
+adc #0
+sta {z1}+1
diff --git a/src/main/fragment/vwsz1=vwsz1_rol_1.asm b/src/main/fragment/vwsz1=vwsz1_rol_1.asm
new file mode 100644
index 000000000..041644ce5
--- /dev/null
+++ b/src/main/fragment/vwsz1=vwsz1_rol_1.asm
@@ -0,0 +1,2 @@
+asl {z1}
+rol {z1}+1
diff --git a/src/main/fragment/vwsz1=vwsz1_rol_2.asm b/src/main/fragment/vwsz1=vwsz1_rol_2.asm
new file mode 100644
index 000000000..e7f769c78
--- /dev/null
+++ b/src/main/fragment/vwsz1=vwsz1_rol_2.asm
@@ -0,0 +1,4 @@
+asl {z1}
+rol {z1}+1
+asl {z1}
+rol {z1}+1
diff --git a/src/main/fragment/vwsz1=vwsz2_rol_1.asm b/src/main/fragment/vwsz1=vwsz2_rol_1.asm
new file mode 100644
index 000000000..0b0cf9a30
--- /dev/null
+++ b/src/main/fragment/vwsz1=vwsz2_rol_1.asm
@@ -0,0 +1,6 @@
+lda {z2}
+asl
+sta {z1}
+lda {z2}+1
+rol
+sta {z1}+1
\ No newline at end of file
diff --git a/src/test/kc/examples/rotate/rotate.kc b/src/test/kc/examples/rotate/rotate.kc
index 056b04563..e0d7d1fef 100644
--- a/src/test/kc/examples/rotate/rotate.kc
+++ b/src/test/kc/examples/rotate/rotate.kc
@@ -40,18 +40,18 @@ void anim() {
 	signed word max = -1000;
 
 	byte angle = 0;
-	signed word x = 89; // signed fixed[15.0]
-	signed word y = 0;
+	signed byte x = 89; // signed fixed[7.0]
+	signed byte y = 0;
 
 	while(true) {
 		while(*RASTER!=$ff) {}
 		(*BORDERCOL)++;	
-		signed word sin_a = (signed word) { SIN_HI[angle], SIN_LO[angle] }; // signed fixed[0.15]
-		signed word cos_a = (signed word)  { COS_HI[angle], COS_LO[angle] }; // signed fixed[0.15]
-		signed dword xr = mulf16s(cos_a, x)<<1 - mulf16s(sin_a, y)<<1; // signed fixed[16.16] 
-		signed dword yr = mulf16s(cos_a, y)<<1 + mulf16s(sin_a, x)<<1; // signed fixed[16.16] 
-		signed word xpos = ((signed word) >xr) + 89 + 24 + 60;
-		signed word ypos = ((signed word) >yr) + 89 + 51;
+		signed byte sin_a = (signed byte) SIN_HI[angle]; // signed fixed[0.7]
+		signed byte cos_a = (signed byte) COS_HI[angle]; // signed fixed[0.7]
+		signed word xr = mulf8s(cos_a, x)<<1 - mulf8s(sin_a, y)<<1; // signed fixed[8.8] 
+		signed word yr = mulf8s(cos_a, y)<<1 + mulf8s(sin_a, x)<<1; // signed fixed[8.8] 
+		signed word xpos = ((signed byte) >xr) + 89 + 24 + 60;
+		signed word ypos = ((signed byte) >yr) + 89 + 51;
        	SPRITES_XPOS[0] = <xpos;
         *SPRITES_XMSB = >xpos;
        	SPRITES_YPOS[0] = <ypos;