Table
G-1.
PET
Memory Map
(Rev
2
ROMs)
(Continued)
Memory Address
Sample Value
Decimal
122-123
124-125
126-127
128-129
130-131
132-133
134-135
136-137
138-139
140-141
142-143
144-145
146-147
148-149
,150-151
152-153
154-155
156
157-158
159-160
161
162
163
164-165
166-171
172-173
174-175
176-181
182
183
184-189
190
191
192-193
Hexadecimal
007A-007B
007C-0070
007E-007F
0080-0081
0082-0083
0084-0085
0086-0087
0088-0089
008A-008B
008C-0080
008E-008F
0090-0091
0092-0093
0094-0095
0096-0097
0098-0099
009A-009B
009C
0090-009E
009F-00AO
OOAl
00A2
00A3
00A4-00A5
00A6-00AB
OOAC-OOAO
OOAE-OOAF
00BO-00B5
00B6
00B7
00B8-00BO
OOBE
OOBF
OOCO-OOCl
Decimal
1025
1946
2072
2231
8192
8191
8192
2000
110
1922
1150
1879
13
89
2032
2032
31999
a
898
104
221
3
76
a
129
a
a
a
a
a
a
a
a
a
a
a
a
a
258
Hexadecimal
0401
079A
0818
08B7
2000
1
FFF
2000
0700
006E
0782
047E
0757
0000
0059
07FO
07FO
7CFF
00
0382
0068
00
03
4C
0000
81
00
00
00
00
00
00
00
00
00
00
00
00
00
0102
Description
Data BASIC Storage Maintenance
Pointer ta start
of
text
Pointer ta start of variables
Pointer ta end
of
variables
Pointer ta end
of
arrays
Pointer
ta
start of strings Imoving downl
Pointer ta end of strings Itop of avadable
RAM)
Pointer ta
limit
of BASIC memory
Line
number
of
current
line
being
executed
-1
in
137=direct
mode statement
Line number for last line executed
before
CO
NT
Pointer ta next line ta
be
executed after
CONT
Line number
of
current OATA line
Pointer
ta
current OATA line
Next OATA item
within
line
Current variable
na
me
Pointer ta current variable
Pointer ta next
FOR.
NEXT variable
Pointer ta current operator in
ROM
table
Mask for current logical operator
Pointer
ta
user function
FN
definition
Pointer
ta
a string description
Length of string
Constant used by garbage collection
routine
Constant 6502 JMP instruction
Jump vector for user function
FN
Floating point accumulator
*3
16
bytes)
Black transfer pointer * 1
Black transfer pomter
*2
Floatmg pomt accumulator
IFAC)
* 1
16
bytes)
176
OOBO
Exponent +128
177
OOB
1 Fraction MSB Floatmg
Pomt
178 00B2 Fraction
179 00B3 Fraction MSB Integer
180 00B4 Fraction
LSB
181
00B5 Sign of fraction
la
if zero or
positive, --1
if
negative)
Copy of
FAC
* 1 slgn of fraction
Counter for number of bits ta shift ta
normalize
FAC
* 1
Floatmg point accumulator
*2
16
bytes)
Overflow byte for floating argument
Copy of
FAC
*2
sign of fraction
Conversion pointer
415
To Next Page
Loading...
