That's the goal... the idea isn't new though

nitpick mode:

Why are you converting the peeked value to a hexadecimal string and compare those, instead of just doing:

1 DEFINT A
120 A=PEEK(&H8000+I)
130 'PRINT HEX$(A)+"|"+CHR$(VAL("&h"+A$)),S
140 IF A=&HEF THEN PRINT"=";:NEXT
(etc.)

Isn't that much faster?

Ok I'm not doing this in basic but in TCL:

I'm really busy with work during the week but have time in the weekends to work on it. It'll work with openMSX only since it supports TCL. If someone wants to code the same for blueMSX just take a look at the TCL code.

(ps it's not working for a long shot but it's a start)

#*****************************************
#* Basic Reader
#*****************************************

# Helper Functions
proc base {base} {
	set base [expr {[peek [expr $base+1]]*256+[peek $base]}]
	return $base
}

proc getEnd {} {
	for {set i [base 0xf676]} {$i < 0xffff} {incr i} {
		if {[base $i]=="0"} {return $i}
	}
}

proc getInit {addr} {
	return [concat [format %x [base $addr]] " :: " [base [expr $addr+2]]]
}

# Main Function
proc getBasic {} {
	set startBasic [base 0xf676]
	set endBasic [getEnd]

	set listing ""

	puts $startBasic
	puts $endBasic

	set newLine 1

	if {$startBasic == $endBasic} {return "No Listing in Memory"}

	for {set addr [expr $startBasic]} {$addr < $endBasic} {incr addr} {
		
		if {$newLine==1} {
			set com [getInit $addr]
			append listing $com
			incr addr 4
			set newLine 0
			
		}

		set addrVal [peek $addr]
	
		set com ""


		if {$addrVal==0x97} {set com "DEF"}
		if {$addrVal==0x8F} {set com "REM"}



		if {$addrVal==0xf1} {set com "+"}
		if {$addrVal==0xf2} {set com "-"}
		if {$addrVal==0xf3} {set com "*"}
		if {$addrVal==0xf4} {set com "/"}
		if {$addrVal==0xf5} {set com "^"}
		if {$addrVal==0xfc} {set com "\\"}

		if {$addrVal==0x20} {set com " "}
		if {$addrVal==0x22} {set com "\""}
		if {$addrVal==0x91} {set com "print"}

		if {$addrVal==0x11} {set com "1"}
		if {$addrVal==0x12} {set com "2"}
		if {$addrVal==0x13} {set com "3"}
		if {$addrVal==0x14} {set com "4"}
		if {$addrVal==0x15} {set com "5"}
		if {$addrVal==0x16} {set com "6"}
		if {$addrVal==0x17} {set com "7"}
		if {$addrVal==0x18} {set com "8"}
		if {$addrVal==0x19} {set com "9"}
		if {$addrVal==0x1a} {set com "0"}
		if {$addrVal==0xef} {set com "="}
		if {$addrVal==0x3a} {set com ":"}

		#BASIC COMMANDS
	if {$addrVal==0xFF || $addrVal==0x3A} {
		#incr addr 1
		#set addrVal [peek $addr]

                                [I cut tokenized BASIC stuff out]

} else {
		if {$addrVal>=0x20 && $addrVal<=0x5A} {set com [format %c $addrVal]}
		if {$addrVal>=0x61 && $addrVal<=0x7A} {set com [format %c $addrVal]}
}

append listing $com

		puts [concat [format %x $addr] " - " [format %x $addrVal] " - " $com]
		if {$addrVal=="0"} {set newLine 1; append listing "\n"}
	}

puts $listing
}

http://openmsx.pastebin.com/f7a4253a3

and done (for now... with 3 todos) Thanks to JoyRex

That problem is weird... SCREEN 3 works, but SCREEN 0 doesn't !?

[edit]

Ah...

I don't know anything about TCL, but...

if {$addrVal==0x1a} {set com "0"}

Shouldn't this be...

if {$addrVal==0x10} {set com "0"}

?

that was my bad...

- if {[byte $addr]>0x11 && [byte $addr]<0x1a} {set tok [expr [byte $addr]-0x11]; set forward 1}
+ if {[byte $addr]>=0x11 && [byte $addr]<=0x1a} {set tok [expr [byte $addr]-0x11]; set forward 1}

The code is now based on JoyRex's script.