From 9b33802dd42b97ad95ae6940cf628923d8093d8a Mon Sep 17 00:00:00 2001
From: John Tsiombikas <nuclear@member.fsf.org>
Date: Thu, 27 Feb 2020 04:31:26 +0200
Subject: [PATCH] bummed some more

---
 dos1/c.asm |   30 +++++++++---------------------
 1 file changed, 9 insertions(+), 21 deletions(-)

diff --git a/dos1/c.asm b/dos1/c.asm
index d7a228f..fb0214f 100644
--- a/dos1/c.asm
+++ b/dos1/c.asm
@@ -1,4 +1,4 @@
-; Lowest yet: 277
+; Lowest yet: 270
 
 	bits 16
 %ifdef BOOTSECT
@@ -41,12 +41,6 @@ start:
 	add ax, 1000h
 	mov es, ax
 
-	; setup palette for the effect
-	; - bg color (0)
-	; - shadow color (1)
-	; - fractal color (2)
-
-
 mainloop:
 	call animate
 
@@ -144,16 +138,21 @@ sierp_vel:
 	dw 1, 1
 	dw -1, 1
 	dw -1, -1
+bounds	dw 200 - SHADOW_OFFS
+	dw 320 - SHADOW_OFFS
+
 
 animate:
 	mov cx, 3
 	mov di, sierp_verts
 	mov si, sierp_vel
 .loop:
+	mov ebx, 2
+.xyloop:
 	mov ax, [di]		; grab vertex X
 	add ax, [si]		; add velocity X
 	jl .xout
-	cmp ax, 320-SHADOW_OFFS
+	cmp ax, [ebx * 2 + bounds - 2]
 	jge .xout
 	jmp .skip_xflip
 .xout:
@@ -165,20 +164,9 @@ animate:
 	; to do the same for Y increment edi and esi by 2
 	add di, 2
 	add si, 2
-	mov ax, [di]		; grab vertex Y
-	add ax, [si]		; add velocity Y
-	jl .yout
-	cmp ax, 200-SHADOW_OFFS
-	jge .yout
-	jmp .skip_yflip
-.yout:
-	sub ax, [si]		; revert to previous Y
-	neg word [si]		; negate velocity Y
-.skip_yflip:
-	mov [di], ax		; update vertex Y
+	dec bx
+	jnz .xyloop
 
-	add di, 2
-	add si, 2
 	dec cx
 	jnz .loop
 	ret
-- 
1.7.10.4