From: Nick Downing <nick@ndcode.org>
Date: Tue, 25 Jun 2019 11:43:29 +0000 (+1000)
Subject: Unroll slightly to avoid an inner loop jump to loop end on zero crossing
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?p=stack_machine.git;a=commitdiff_plain

Unroll slightly to avoid an inner loop jump to loop end on zero crossing
---

diff --git a/sm3.asm b/sm3.asm
index f8866db..0a622b7 100644
--- a/sm3.asm
+++ b/sm3.asm
@@ -2438,7 +2438,15 @@ div_w00:
 	sbc	hl,bc
 	jr	nc,div_w02
 	dec	a
-	jr	div_w12
+	;jr	div_w12
+	add	a,a
+	dec	d
+	jr	nz,div_w10
+	;inc	a
+	;dec	a			; compensation
+	scf
+	pop	de
+	ret
 div_w01:
 	or	a
 	sbc	hl,bc
@@ -2461,7 +2469,14 @@ div_w10:
 	add	hl,bc
 	jr	nc,div_w12
 	inc	a
-	jr	div_w02
+	;jr	div_w02
+	add	a,a
+	dec	d
+	jr	nz,div_w00
+	dec	a
+	or	a
+	pop	de
+	ret
 div_w11:
 	add	hl,bc
 div_w12:
@@ -2488,7 +2503,15 @@ div_w_n00:
 	sbc	hl,bc
 	jr	c,div_w_n02
 	dec	a
-	jr	div_w_n12
+	;jr	div_w_n12
+	add	a,a
+	dec	d
+	jr	nz,div_w_n10
+	;inc	a
+	;dec	a			; compensation
+	scf
+	pop	de
+	ret
 div_w_n01:
 	sbc	hl,bc
 div_w_n02:
@@ -2510,7 +2533,14 @@ div_w_n10:
 	add	hl,bc
 	jr	c,div_w_n12
 	inc	a
-	jr	div_w_n02
+	;jr	div_w_n02
+	add	a,a
+	dec	d
+	jr	nz,div_w_n00
+	dec	a
+	or	a
+	pop	de
+	ret
 div_w_n11:
 	add	hl,bc
 div_w_n12:
@@ -2962,7 +2992,15 @@ div_l00:
 	exx
 	jr	nc,div_l02
 	dec	a
-	jr	div_l12
+	;jr	div_l12
+	add	a,a
+	dec	d
+	jr	nz,div_l10
+	;inc	a
+	;dec	a			; compensation
+	scf
+	pop	de
+	ret
 div_l01:
 	or	a
 	sbc	hl,bc
@@ -2994,7 +3032,14 @@ div_l10:
 	exx
 	jr	nc,div_l12
 	inc	a
-	jr	div_l02
+	;jr	div_l02
+	add	a,a
+	dec	d
+	jr	nz,div_l00
+	dec	a
+	or	a
+	pop	de
+	ret
 div_l11:
 	add	hl,bc
 	exx
@@ -3030,7 +3075,15 @@ div_l_n00:
 	exx
 	jr	c,div_l_n02
 	dec	a
-	jr	div_l_n12
+	;jr	div_l_n12
+	add	a,a
+	dec	d
+	jr	nz,div_l_n10
+	;inc	a
+	;dec	a			; compensation
+	scf
+	pop	de
+	ret
 div_l_n01:
 	sbc	hl,bc
 	exx
@@ -3061,7 +3114,14 @@ div_l_n10:
 	exx
 	jr	c,div_l_n12
 	inc	a
-	jr	div_l_n02
+	;jr	div_l_n02
+	add	a,a
+	dec	d
+	jr	nz,div_l_n00
+	dec	a
+	or	a
+	pop	de
+	ret
 div_l_n11:
 	add	hl,bc
 	exx