$:.unshift(File.dirname(__FILE__)) unless
	$:.include?(File.dirname(__FILE__)) || $:.include?(File.expand_path(File.dirname(__FILE__)))

$:.unshift(File.dirname(__FILE__+"\\..")) unless
	$:.include?(File.dirname(__FILE__+"\\..")) || $:.include?(File.expand_path(File.dirname(__FILE__+"\\..")))


require 'HostSystem'
class Zx81<HostSystem

def self.full_name
    "Sinclair ZX81"
end  

def self.tokens 
  {
0=>' ',
11=>'"',
12=>'£',
13=>'$',
14=>':',
15=>'?',
16=>'(',
17=>')',
18=>'>',
19=>'<',
20=>'=',
21=>'+',
22=>'-',
23=>'*',
24=>'/',
25=>';',
26=>',',
27=>'.',
28=>'0',
29=>'1',
30=>'2',
31=>'3',
32=>'4',
33=>'5',
34=>'6',
35=>'7',
36=>'8',
37=>'9',
38=>'A',
39=>'B',
40=>'C',
41=>'D',
42=>'E',
43=>'F',
44=>'G',
45=>'H',
46=>'I',
47=>'J',
48=>'K',
49=>'L',
50=>'M',
51=>'N',
52=>'O',
53=>'P',
54=>'Q',
55=>'R',
56=>'S',
57=>'T',
58=>'U',
59=>'V',
60=>'W',
61=>'X',
62=>'Y',
63=>'Z',
64=>'RND ',
65=>'INKEY$ ',
66=>'PI ',
112=>'<cursor up>',
113=>'<cursor down>',
114=>'<cursor left>',
115=>'<cursor right>',
116=>'GRAPHICS ',
117=>'EDIT ',
118=>'NEWLINE ',
119=>'RUBOUT ',
120=>'/',
121=>'FUNCTION ',
127=>'cursor',
128=>' ',
139=>'"',
140=>'£',
141=>'$',
142=>':',
143=>'?',
144=>'(',
145=>')',
146=>'>',
147=>'<',
148=>'=',
149=>'+',
150=>'-',
151=>'*',
152=>'/',
153=>';',
154=>',',
155=>'.',
156=>'0',
157=>'1',
158=>'2',
159=>'3',
160=>'4',
161=>'5',
162=>'6',
163=>'7',
164=>'8',
165=>'9',
166=>'A',
167=>'B',
168=>'C',
169=>'D',
170=>'E',
171=>'F',
172=>'G',
173=>'H',
174=>'I',
175=>'J',
176=>'K',
177=>'L',
178=>'M',
179=>'N',
180=>'O',
181=>'P',
182=>'Q',
183=>'R',
184=>'S',
185=>'T',
186=>'U',
187=>'V',
188=>'W',
189=>'X',
190=>'Y',
191=>'Z',
192=>'""',
193=>'AT ',
194=>'TAB ',
195=>'?',
196=>'CODE ',
197=>'VAL ',
198=>'LEN ',
199=>'SIN ',
200=>'COS ',
201=>'TAN ',
202=>'ASN ',
203=>'ACS ',
204=>'ATN ',
205=>'LN ',
206=>'EXP ',
207=>'INT ',
208=>'SQR ',
209=>'SGN ',
210=>'ABS ',
211=>'PEEK ',
212=>'USR ' ,
213=>'STR$ ',
214=>'CHR$ ',
215=>'NOT ',
216=>'**',
217=>'OR ',
218=>'AND ',
219=>'<=',
220=>'>=',
221=>'<>',
222=>'THEN ',
223=>'TO ',
224=>'STEP ',
225=>'LPRINT ',
226=>'LLIST ',
227=>'STOP ',
228=>'SLOW ',
229=>'FAST ',
230=>'NEW ',
231=>'SCROLL ',
232=>'CONT ',
233=>'DIM ',
234=>'REM ',
235=>'FOR ',
236=>'GOTO ' ,
237=>'GOSUB ' ,
238=>'INPUT ',
239=>'LOAD ',
240=>'LIST ',
241=>'LET ',
242=>'PAUSE ',
243=>'NEXT ',
244=>'POKE ',
245=>'PRINT ',
246=>'PLOT ',
247=>'RUN ',
248=>'SAVE ',
249=>'RAND ',
250=>'IF ',
251=>'CLS ',
252=>'UNPLOT ',
253=>'CLEAR ',
254=>'RETURN ',
255=>'COPY ',
}

end
def self.start_track
    0
end

def self.to_ascii(b)
  token=tokens[b]
  if (!token.nil?) && (token.length==1) then
    token
  else
    "."
  end
end 

#decode 5 bytes as a number
#A number is stored in the ZX81 in floating point binary with one exponent byte e (1 <=e <=255), & four mantissa bytes m (½ <= m <= 1). This represents the number m * 2**(e-128.)
# Since ½<= m<=1, the most significant bit of the mantissa m is always 1. Therefore in actual fact we can replace it with a bit to show the sign - 0 for positive numbers, 1 for negative. 
#Zero has a special representation in which all 5 bytes are 0. 
#this is a conversion of code originally posted by Darren Salt to http://groups.google.com.au/group/comp.sys.sinclair/browse_frm/thread/37966a7bb023670d/690f27c27f48a036
def self.buffer_to_number(buffer)
  raise "invalid number length" unless buffer.length==5
  if buffer[0]==0 then #it's an integer between -65535 & 65535
      return buffer[3] * 256 + buffer[2] - (buffer[1]==0 ? 65536 : 0); 
  else  
    exponent=buffer[0]-128
    sign = (buffer[1] >=0x80) ? -1 : 1
    mantissa = ((buffer[1] | 0x80) / 256.0) + (buffer[2] / 65536.0 ) + (buffer[3] / 16777216.0) + (buffer[4] / 4294967296.0)
    value = sign * mantissa * (2**exponent)
    return value.to_i if (value.to_i.to_f==value)
    return value
  end
  
end

end  
# == Author
# Jonno Downes (jonno@jamtronix.com)
#
# == Copyright
# Copyright (c) 2008 Jonno Downes (jonno@jamtronix.com)
#
#Permission is hereby granted, free of charge, to any person obtaining
#a copy of this software and associated documentation files (the
#"Software"), to deal in the Software without restriction, including
#without limitation the rights to use, copy, modify, merge, publish,
#distribute, sublicense, and/or sell copies of the Software, and to
#permit persons to whom the Software is furnished to do so, subject to
#the following conditions:

# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.