From 40eda1d9339fbfa9da2ae9313089303f8c7cbe37 Mon Sep 17 00:00:00 2001
From: Virgil Dupras <hsoft@hardcoded.net>
Date: Thu, 26 Mar 2020 14:36:14 -0400
Subject: [PATCH] forth: Forth-ify "*"

---
 emul/forth/z80c.bin | Bin 367 -> 401 bytes
 forth/forth.asm     |  28 +---------------------------
 forth/z80c.fs       |  21 +++++++++++++++++++++
 3 files changed, 22 insertions(+), 27 deletions(-)

diff --git a/emul/forth/z80c.bin b/emul/forth/z80c.bin
index f8a2b42e9256f24d613ab1402e5c78e6f8739e5a..f9c283090158d34da3e8f2a376d11a35121bd48c 100644
GIT binary patch
delta 49
zcmV-10M7sK0+9odq$es8009>O(ZS6f03iSXJ`gF(6U!1X1PL$!6FngE<--~PFHKKG
HB9W=aUJVY%

delta 15
XcmbQp{GMsT5>|a*e;3h-r;h;uEZhbK

diff --git a/forth/forth.asm b/forth/forth.asm
index 31f53dc..742804f 100644
--- a/forth/forth.asm
+++ b/forth/forth.asm
@@ -1340,35 +1340,9 @@ MINUS:
 	push	hl
 	jp	next
 
-; ( a b -- c ) A * B
-	.db "*"
-	.dw $-MINUS
-	.db 1
-MULT:
-	.dw nativeWord
-	pop	de
-	pop	bc
-	call	chkPS
-	; DE * BC -> DE (high) and HL (low)
-	ld	hl, 0
-	ld	a, 0x10
-.loop:
-	add	hl, hl
-	rl	e
-	rl	d
-	jr	nc, .noinc
-	add	hl, bc
-	jr	nc, .noinc
-	inc	de
-.noinc:
-	dec a
-	jr	nz, .loop
-	push	hl
-	jp	next
-
 ; ( a1 a2 -- b )
 	.db "SCMP"
-	.dw $-MULT
+	.dw $-MINUS
 	.db 4
 SCMP:
 	.dw nativeWord
diff --git a/forth/z80c.fs b/forth/z80c.fs
index 1ed407a..fbe7ac5 100644
--- a/forth/z80c.fs
+++ b/forth/z80c.fs
@@ -113,6 +113,27 @@ CODE XOR
     HL PUSHqq,
 ;CODE
 
+CODE *
+    DE POPqq,
+    BC POPqq,
+    chkPS,
+	( DE * BC -> DE (high) and HL (low) )
+    HL 0 LDddnn,
+    A 0x10 LDrn,
+( loop )
+    HL ADDHLss,
+    E RLr,
+    D RLr,
+    6 JRNCe, ( noinc )
+    BC ADDHLss,
+    3 JRNCe, ( noinc )
+    DE INCss,
+( noinc )
+    A DECr,
+    0 12 - JRNZe, ( loop )
+    HL PUSHqq,
+;CODE
+
 ( Borrowed from http://wikiti.brandonw.net/ )
 ( Divides AC by DE and places the quotient in AC and the
   remainder in HL )