From f33961b549672c23d768bdfe2c2880db9a58ff6e Mon Sep 17 00:00:00 2001
From: Leo C
Date: Thu, 29 Nov 2018 20:10:02 +0100
Subject: Improved div_hl_de

---
 ddt180.z80 | 51 ++++++++++++++++++++++-----------------------------
 1 file changed, 22 insertions(+), 29 deletions(-)

diff --git a/ddt180.z80 b/ddt180.z80
index 246ff90..e624c8b 100644
--- a/ddt180.z80
+++ b/ddt180.z80
@@ -999,40 +999,33 @@ doop_mod:
 ;     de: r  (x%y)
 
 div_hl_de:
-	push bc
-	ex de,hl
-	ld b,h
-	ld c,l
-	ld hl,0
-	ld a,16
+	push	bc
+	ex	de,hl		;de: x
+	ld	b,h		;bc: y
+	ld	c,l
+	ld	hl,0		;hl: r
+	ld	a,16
 
 ;  de: x   (x shifted out, q shifted in)
 ;  bc: y
 ;  hl: r   (initially 0)
 
-l047eh:
-	push af
-	add hl,hl
-	ex de,hl
-	xor a
-	add hl,hl
-	ex de,hl
-	adc a,l
-	sub c
-	ld l,a
-	ld a,h
-	sbc a,b
-	ld h,a
-	inc de
-	jr nc,l048fh
-	add hl,bc
-	dec de
-l048fh:
-	pop af
-	dec a
-	jr nz,l047eh
-	ex de,hl
-	pop bc
+div_lp:
+	ex	de,hl
+	add	hl,hl		;x <<= 1
+	ex	de,hl
+	adc	hl,hl		;r <<= 1
+	inc	de
+	or	a
+	sbc	hl,bc
+	jr 	nc,div_norestore
+	dec	de
+	add	hl,bc
+div_norestore:
+	dec	a
+	jr	nz,div_lp
+	ex	de,hl
+	pop	bc
 	ret
 
 doop_and:
-- 
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