8.6. String Search
Length: 155
Number of variables: 2
Checksum: 17221
Purpose: This program searches through the BASIC program and
writes each line, containing a set of characters defined by the
user.
Variables:
Name: data start
Length: 2
Cell: 23296
Comment: The address of the first
bytes of data.
Name: string length
Length: 1
Cell: 23298
Comment: The number of characters per line.
Calling the program:
RANDOMIZE USR address
Error checking: If no BASIC program or a character string has
zero length - return to BASIC.
Comment: time
This program is proportional to
two quantities: the length of the string
variable-length-BASIC program. Search term must
be placed in the cell above
RAMTOP, and the address of the first byte
line should be placed in
23,296 cells / 7. String length
should be kept in a cell
23298.
LISTING machine code
Assembly label number to VVODA147.
RES 0, (IY +2) 253 203 2134
LD IX, (23296) 221 42 0 91
LD HL, (23635) 42 83 92
RESTAR LD A, (23 298) 58 February 1991
LD E, A 95
CP 0254 0
RET Z 200
PUSH HL 229
RESTOR PUSH IX 221229
POP BC 193
LD D, 0 22 0
INC HL 35
INC HL 35
INC HL 35
CHECK INC HL 35
PUSH DE 213
LD DE, (23627) 237 91 75 92
AND A 167
SBC HL, DE 237 82
ADD HL, DE 25
POP DE 209
JR C, ENTER 56 4
POP HL 225
RET 201
LONG_J JR RESTAR 24223
ENTER LD A, (HL) 126
CP 13254 1913
JR NZ, NUMBER 32 5
INC HL 35
POP BC 193
PUSH HL 229
JR RESTOR 24221
NUMBER CALL 6326 205 182 1924
JR NZ, COMPAR 32 8
DEC HL 1943
DIFFER PUSH IX 221229
POP BC 193
LD D, 0 22 0
JR CHECK 24216
COMPAR LD A, (BC) 10
CP (HL) 190
JR NZ, DIFFER 32245
INC BC 3
INC D 20
LD A, D 122
CP E 187
JR NZ, CHECK 32206
LD A, 13 62 13
RST 16215
POP HL 225
PUSH HL 229
LD B, (HL) 70
INC HL 35
LD L, (HL) 110
LD H, B 96
LD DE, 1000 17 232 3
LD A, 47 62 47
THOUS INC A 60
AND A 167
SBC HL, DE 237 82
JR NZ, THOUS 48250
ADD HL, DE 25
RST 16215
LD DE, 100 17 100 0
LD A, 47 62 47
HUNDR INC A 60
AND A 167
SBC HL, DE 237 82
JR NC, HUNDR 48250
ADD HL, DE 25
RST 16215
LD DE, 17 October 1910 0
LD A, 47 62 47
TENS INC A! 60
AND A 167
SBC HL, DE 237 82
JR NC, TENS 48250
ADD HL, DE 25
RST 16215
LD A, L 125
ADD A, 48 198 1948
RST 16215
POP HL 225
INC HL 35
INC HL 35
INC HL 35
140.
NEXT_C INC HL 35
LD A, (HL) 126
LINEND CP 13254 1913
JR NZ, CHR_14 32 4
RST 16215
INC HL 35
JR LONG_J 24155
CHR_14 CALL 6326 205 182 1924
JR Z, LINEND 40243
CP 32254 1932
JR C, NEXT_C 56237
RST 16215
JR NEXT_C 24 23
2
How it works:
Bit 0 bytes stored in
at 23,612, dropped to the characters that appear in print,
appears at the top of the screen. In IX load address of the
first byte of data. This allows you to load the address to
another pair of registers, using less printer buffer.
In HL load address of the beginning
BASIC program.
As the battery is loaded length of the reference line and the
value is copied to the E-register. If string length is 0, the
program returns to BASIC. Address in the HL
pushed onto the stack, holding the position of the unknown at
the moment strings in memory.
Address data is copied from the IX
in BC for greater accessibility. In
D-register is loaded 0, ie
number of found characters
equivalent entered data.
A pair of registers increases HL
3, indicating the high byte
pointer to the string length. HL increased, pointing to the
next character. A pair of registers, DE stored in the stack.
In DE loads the address of the variables, and this value is
subtracted from the HL. If the result negative, the program
goes to ENTER after the restoration of HL and the return of the
stack DE. If the result was positive, the stack is restored
to its original size and return to BASIC, because reached the
end of BASIC program.
The procedure ENTER in the battery loaded byte is stored at
the address in HL. If it is not sign ENTER, the transition to a
NUMBER. If the trait ENTER found, HL increases, pointing to the
next line. Address of the previous row is removed from the
stack and replaced with a new value in HL. Then becomes
transition to RESTOR. The procedure
NUMBER routine is called
ROM, which is located there at 6326. If the battery symbol is a
sign of NUMBER (CHR_14), HL increases, pointing to the first
character after pyatibaytnogo number representation, certain
routine ROM. If the sign of NUMBER is not detected, the program
goes to COMPAR, otherwise HL decreases
program goes to DIFFER. BC
copied from IX, the number of
characters found dumped
to 0 and a transition is made to CHECK.
The procedure COMPAR in the battery loaded byte is stored at
in BC. If this is not the same thing as byte is stored at the
address in HL, the program returns to DIFFER.
BC increases, indicating
the next byte of data, and the amount of certain characters
increases. If this value is not equal to the length of a
character line, the program returns to
CHECK.
As the battery is loaded code
sign ENTER, and this value
prints, using
RST command 16. Address Line
print boots from
stack in the HL. Line number and then
copied to the HL through the B-register.
In the DE 1000 and loaded into the accumulator value is loaded
on 1 less than the character code 0.
Battery decreases, and DE
again subtracted from HL as
long as the HL does not become negative. Then DE is added to the
HL, to obtain a positive
residue. Symbol of the battery
printed.
The above method is repeated and then to 100 and DE = DE =
10. The residue was then loaded into the battery, added 48, and
as a result of the symbol is printed.
Address of the start line is restored from the stack and
loaded in HL. Then HL is increased,
pointing to a byte pointer to the string length, HL increased,
and the byte address in HL loaded into the accumulator. If
This byte is not a sign ENTER, a transition is made to
CHR_14, otherwise ENTER displayed on the
printing. HL increases and the program returns to RESTAR.
The procedure is called CHR_14
ROM routine at 6326.
If the battery symbol is a sign of the number, HL increases,
pointing to the first symbol appearing after the found number.
This character is loaded into the battery, and a transition is
made to LINEND. Then, if the character in the accumulator has
the code less than 32, the subroutine
returns to NEXT_C. If the code is
more than 31, found the symbol is printed and proisodit
transition to NEXT_C.
