From c29dcb65c8e96420a8dff5867a56193aa8f58315 Mon Sep 17 00:00:00 2001
From: David Schmenk <dschmenk@gmail.com>
Date: Mon, 16 Jun 2014 10:29:04 -0700
Subject: [PATCH] Move DROP to ZP

---
 src/vmsrc/plvm01.s   | 11 ++++++-----
 src/vmsrc/plvm02.s   | 11 ++++++-----
 src/vmsrc/plvm03.s   | 15 ++++++++-------
 src/vmsrc/plvmzp.inc |  1 +
 4 files changed, 21 insertions(+), 17 deletions(-)

diff --git a/src/vmsrc/plvm01.s b/src/vmsrc/plvm01.s
index dd796ce..20f00c2 100644
--- a/src/vmsrc/plvm01.s
+++ b/src/vmsrc/plvm01.s
@@ -184,7 +184,7 @@ ADD 	LDA	ESTKL,X
 	LDA	ESTKH,X
 	ADC	ESTKH+1,X
 	STA	ESTKH+1,X
-DROP	INX
+	INX
 	JMP	NEXTOP
 ;*
 ;* SUB TOS FROM TOS-1
@@ -923,9 +923,9 @@ LEAVE 	LDY	#$01
 RET 	RTS
 A1CMD	!SOURCE	"vmsrc/a1cmd.a"
 SEGEND	=	*
-VMINIT	LDY	#$0D		; INSTALL PAGE 0 FETCHOP ROUTINE
+VMINIT	LDY	#$0E		; INSTALL PAGE 0 FETCHOP ROUTINE
 - 	LDA	PAGE0,Y
-	STA	NEXTOP,Y
+	STA	DROP,Y
 	DEY
 	BPL	-
 	LDA	#$00		; INIT FRAME POINTER
@@ -939,11 +939,12 @@ VMINIT	LDY	#$0D		; INSTALL PAGE 0 FETCHOP ROUTINE
         LDX	#ESTKSZ/2	; INIT EVAL STACK INDEX
 	JMP	A1CMD
 PAGE0	=	*
-       	!PSEUDOPC	$00F0 {
+       	!PSEUDOPC	$00EF {
 ;*
 ;* INTERP BYTECODE INNER LOOP
 ;*
-	INY
+	INX			; DROP
+	INY			; NEXTOP
 	BEQ	NEXTOPH
 FETCHOP LDA	(IP),Y
 	STA	OPIDX
diff --git a/src/vmsrc/plvm02.s b/src/vmsrc/plvm02.s
index 9ca82fd..e42ff64 100644
--- a/src/vmsrc/plvm02.s
+++ b/src/vmsrc/plvm02.s
@@ -253,9 +253,9 @@ CMDEXEC	=	*
 ;
 ; INSTALL PAGE 0 FETCHOP ROUTINE
 ;
-	LDY	#$0D
+	LDY	#$0E
 - 	LDA	PAGE0,Y
-	STA	NEXTOP,Y
+	STA	DROP,Y
 	DEY
 	BPL	-
 ;
@@ -316,11 +316,12 @@ DISABLE80 !BYTE	21, 13, '1', 26, 13
 FAILMSG !BYTE	39
 	!TEXT	"MISSING CMD. PRESS ANY KEY TO RESET..."
 PAGE0	=	*
-       	!PSEUDOPC	$00F0 {
+       	!PSEUDOPC	$00EF {
 ;*
 ;* INTERP BYTECODE INNER LOOP
 ;*
-	INY
+	INX			; DROP @ $EF
+	INY			; NEXTOP @ $F0
 	BEQ	NEXTOPH
 FETCHOP LDA	(IP),Y
 	STA	OPIDX
@@ -368,7 +369,7 @@ ADD 	LDA	ESTKL,X
 	LDA	ESTKH,X
 	ADC	ESTKH+1,X
 	STA	ESTKH+1,X
-DROP	INX
+	INX
 	JMP	NEXTOP
 ;*
 ;* SUB TOS FROM TOS-1
diff --git a/src/vmsrc/plvm03.s b/src/vmsrc/plvm03.s
index f73c028..d7e5716 100644
--- a/src/vmsrc/plvm03.s
+++ b/src/vmsrc/plvm03.s
@@ -14,7 +14,7 @@ MEMBANK =	$FFEF
 ; XPAGE ADDRESSES
 ;
 XPAGE	=	$1600
-NEXTOPX	=	XPAGE+NEXTOP
+DROPX	=	XPAGE+DROP
 IFPX	=	XPAGE+IFPH
 IPX	=	XPAGE+IPH
 TMPX	=	XPAGE+TMPH
@@ -50,11 +50,11 @@ DSTX	=	XPAGE+DSTH
 	BNE	PRHEX
 	LDA	#$01
 	STA	MEMBANK
-	LDY	#$0D		; INSTALL PAGE 0 FETCHOP ROUTINE
+	LDY	#$0E		; INSTALL PAGE 0 FETCHOP ROUTINE
 	LDA	#$00
 - 	LDX	PAGE0,Y
-	STX	NEXTOP,Y
-	STA	NEXTOPX,Y
+	STX	DROP,Y
+	STA	DROPX,Y
 	DEY
 	BPL	-
 	STA	TMPX		; CLEAR ALL EXTENDED POINTERS
@@ -73,11 +73,12 @@ SEGREQ	!BYTE	4
 	!BYTE	$10
 	!BYTE	$00
 PAGE0	=	*
-       	!PSEUDOPC	$00F0 {
+       	!PSEUDOPC	$00EF {
 ;*
 ;* INTERP BYTECODE INNER LOOP
 ;*
-	INY
+	INX			; DROP
+	INY			; NEXTOP
 	BEQ	NEXTOPH
 FETCHOP LDA	(IP),Y
 	STA	OPIDX
@@ -271,7 +272,7 @@ ADD 	LDA	ESTKL,X
 	LDA	ESTKH,X
 	ADC	ESTKH+1,X
 	STA	ESTKH+1,X
-DROP	INX
+	INX
 	JMP	NEXTOP
 ;*
 ;* SUB TOS FROM TOS-1
diff --git a/src/vmsrc/plvmzp.inc b/src/vmsrc/plvmzp.inc
index 5fc6d17..9667f31 100644
--- a/src/vmsrc/plvmzp.inc
+++ b/src/vmsrc/plvmzp.inc
@@ -28,6 +28,7 @@ NPARMS	=	TMPL
 FRMSZ	=	TMPH
 DVSIGN	=	TMP+2
 ESP     =       TMP+2
+DROP	=	$EF
 NEXTOP	=	$F0
 OPIDX	=	NEXTOP+8
 OPPAGE	=	OPIDX+1