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ZX Review #7-8-9-10
08 ноября 1997 |
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reader-reader - Print numbers in different number systems.
(C) Kolotov Sergei g.Shadrinsk,
SerzhSoft, V, 1997.
PRINT NUMBERS IN DIFFERENT
Radix
One of the most important computer tasks is to derive the
numbers screen (printing). Where the numbers
can be presented in various
number systems, of which there are not so little.
The most familiar of all
We, of course, is a decimal system, ie system
radix base 10. Ten here appears no accident: the man from
ancient times believed the finger hands, as they are known -
ten. But the computer "habitual" assumed to be in the decimal
system, and in binary, because all the information in it is the
electric charges: is the current (1) and no current (0). So how
do translated from "a computer" language to normal man?
The following procedure prints the numbers given
register A (accumulator) in decimal form. Printing to a
standard command RST # 10 in the current output stream. The
length of the procedure, 23 bytes. In its work, she uses a
3-byte table of ten degrees, and if
performance, in a series of counts and the number of prints
hundred (first digit), tens of
(Second) and units (third digit)
numbers.
See Listing 1.
Yet it is unlikely that
and not be a need
print, say, in hexadecimal or binary systems
notation. Yes, even in the same
decimal, but, for example, numbers
the range is not between 0 and 255, and from
0 to 65535. Therefore, it suffices
advisable to always "have a
hand "library of procedures
intended for printing numbers in a variety of systems
notation, in various
ranges. What me and realized ...
See Listing 2.
The composition of the library
includes procedures for the printing of numbers in a variety of
systems notation. Namely: decimal,
hex, binary, set by the user (eg, octal) and, as
particularly exotic, the system Roman numbers.
Procedures that make up the library, have much in common, and
fully understand the one,
can more quickly grasp the
principle of the rest. All
print headlines procedures begin with the P (Print). Further
there are three letters that define a system in which the
number of prints. Then separated underscore character, you
should one of the symbols B and W, define a range of printed
numbers: Byte (Byte), or the word (Word). In the first case (B)
before calling the procedure, the number should be in the
register A (accumulator), and in the second case (W) - in the
register pair HL. Printing is the current output stream
(command RST # 10).
Library description PDES LIB
1. Print decimal
1) The procedure PDEC_W - print
numbers in the results
gistrovoy pair HL. Range
Zones print: 00000 .. 65535.
The length of the procedure, 26 bytes.
Uses a table of degree
It tens DECTB_W.
2) Procedure PDEC_B - print
the number of A (000 .. 255), 10
bytes. In his work vyzy
Vaeth PDEC_W.
3) Table DECTB_W - contains
5 degrees of scores given by
GOVERNMENTAL as words (2 bytes) -
length of 10 bytes.
Total length of section: 10 10 26
= 46 bytes.
2. Print hex
numbers
1) Pr-pa PHEX_LB - printing ml.
nibble in A (0 .. F), 14
bytes.
2) Pr-pa PHEX_HB - print art.
nibble in A (0 .. F), 4
bytes. Swaps on
lubayty A and causes
PHEX_LB.
3) Pr-pa PHEX_B - print number
la in A (00 .. FF), 3 bytes.
Two times is PHEX_HB.
4) Pr-pa PHEX_W - print number
la in the HL (0000 .. FFFF), 5
bytes. Two times is
PHEX_B.
Total length of section: 5 +3 +4 14
= 26 bytes.
3. Print binary numbers
1) Pr-pa PBIN_B - print number
la in A (8 bits), 12
bytes.
2) Pr-pa PBIN_W - print number
la in HL (16 bits), 5
bytes. Two times is
PBIN_B.
Total length of section: 5 +12 = 17
bytes.
4. Print numbers in radix set by the user.
Served as a prototype for the procedure, published in an
excellent reference - book Rodionova
and A. Larchenko "ZX-Spectrum for
users and programmers. "
1) Pr-pa MKUSETB - filling
Table degrees USE_TBL with
grounds specified in the active
kumulyatore. The length of the pr-algebra 28
bytes.
2) Pr-pa PUSE_W - print number
la in HL. Uses previously
created MKUSETB table
degrees USE_TBL. 33 bye
Ta.
3) Table USE_TBL - Table
degrees, 32 bytes.
Total length of section: 32 33 28
= 93 bytes.
5. Printing Roman numerals
1) Pr-pa PRIM_W - print number
la in the HL (I.. MMMCMXCIX), 77
bytes. Uses a table
RIM_TBL.
2) Pr-pa PRIM_B - print number
la in A (I.. CCLV). Length 3
bytes. Calls the procedure
PRIM_W.
3) Table RIM_TBL - Table
significance of letters in napisa
Institute of Roman numerals. Length:
7 * 3 = 21 bytes.
Total length of section: 21 3 77
= 101 bytes.
Full size libraries: 283
bytes.
140.
Listing 1. The printing process bytes in decimal.
PDEC_B; print a decimal number to akkumulyatore3 (000 .. 255)
LD HL, DECTB_B; address table tens of degrees
LD B, # 03; max. possible number of digits
LP_PDB1 LD C, "0" -1; initialize counter
LP_PDB2 INC C; increments
SUB (HL); subtract the current level of tens of
JR NC, LP_PDB2; repeat until A> = 0
ADD A, (HL); A = A mod (HL); C = STR $ (A div (HL))
PUSH AF; keep A on the stack
LD A, C; the current figure
RST # 10; print figures
POP AF; restore battery
INC HL; move to the next. tens of degrees
DJNZ LP_PDB1; twisted loop on the numbers
RET; exit procedures
;
DECTB_B DB 100,10,1; Table stepeney3 10-ki for a byte
Listing 2. Library of print in different number systems.
;------ PDES LIB -----; Printing in Different Evaluation
Systems LIBrary ; (C) SerzhSoft, Shadrinsk, V, March 1997
;
_NULL EQU 0; used in changing teams
;
; --- Print in DEC system -;
PDEC_B; print a decimal number to A3 (000 .. 255)
LD L, A; placed
LD H, # 00; the number of HL
LD DE, DECTB_W +4; address in the table, starting with
hundreds of
LD B, # 03; max. possible number of digits - three
JR LP_PDW1; go to print cycle
;
PDEC_W; print a decimal number in HL3 (00000 .. 65535)
PUSH HL; threw the printed number on the stack
LD HL, DECTB_W; address table tens of degrees
LD B, # 05; max. possible number of digits
LP_PDW1 LD E, (HL); took the current degree of
INC HL; dozens of tables
LD D, (HL); and placed in DE
INC HL; moved on to trace. element table
EX (SP), HL; your e-ma <-> prints the number of
XOR A; reset the counter and a flag C for SBC
LP_PDW2 INC A; increments
SBC HL, DE; subtract the current level of tens of
JR NC, LP_PDW2; repeat until HL> = 0
ADD HL, DE; HL = HL mod DE; A = HL div DE
ADD A, "0" -1; A translation into ASCII-code ("0" ..
"9")
RST # 10; printing decimal numbers
EX (SP), HL; HL = address of E-one number - "on the
stack
DJNZ LP_PDW1; cycle by the numbers
POP HL; removed the remainder of the zero from the stack
RET; exit procedures
;
DECTB_W DW 10000,1000,100,10,1; Table of tens of degrees
;
; --- Print in HEX system -;
PHEX_W; Printing hexadecimal numbers in HL3 (0000 .. FFFF)
LD A, H; print high byte of
CALL PHEX_B; procedure call HEX-printing bytes
LD A, L; print low byte of
;
PHEX_B; Print a hexadecimal number in A3 (00 .. FF)
CALL PHEX_HB; print on nibble
;
PHEX_HB; print high-order nibble into A3 (0 .. F)
RRCA; change
RRCA; places
RRCA; Senior
RRCA; and minor nibbles
;
PHEX_LB; Print younger nibble into A3 (0 .. F)
PUSH AF; saved on the stack A
AND # 0F; threw extra high-order bits
CP # 0A; if A <10,
JR C, GO_PHL; then jumped
ADD A, "A" - "9" -1; adjustment: after the "9" is "A"
GO_PHL ADD A, "0", translated into ASCII-code
RST # 10; print HEX-digits ("0" .. "F")
POP AF; A restored from the stack
RET; exit procedures
;
; --- Print in BIN system -;
PBIN_W; print binary number to HL (16-bit 0 / 1)
LD A, H; print high byte of
CALL PBIN_B; procedure call BIN-printing bytes
LD A, L; print low byte of
;
PBIN_B; print binary number in A (8 bits 0 / 1)
LD B, # 08; in a byte - 8 bits
LP_PBB RLCA; alternately 'posit' bits in the CF
PUSH AF; keep A on the stack
LD A, # 18, depending on the flag C:
RLA; A = "0" or A = "1"
RST # 10; print the next bit
POP AF; recover A from the stack
DJNZ LP_PBB; bitwise cycle
RET; exit procedures
;
; --- Print in USER system -;
PUSE_W; Seal of the installed system MKUSETB Acc-I in HL
PUSH HL; threw the printed number on the stack
HL_PUW LD HL, _NULL; address of the end of the table of degrees
LP_PUW1 DEC HL; load at DE next
LD D, (HL); degree of
DEC HL; from the table,
LD E, (HL); moving 'top-down'
EX (SP), HL; address table <-> print-e number
XOR A; A reset and reset the flag C
LP_PUW2 INC A; compute the next
SBC HL, DE; digit numbers and the result
JR NC, LP_PUW2; put it in A (A = 1 + (HL div DE))
ADD HL, DE; restore (+) value
ADD A, "0" -1; translating A in ASCII-code
CP "9" +1, if the code is less than "9"
JR C, GO_PUW1; then go to print
ADD A, "A" - "9" -1; correction (after the "9" is "A")
GO_PUW1 RST # 10; print the next digit numbers
EX (SP), HL; HL = address table, the number -> stack
DEC DE; if the degree of
LD A, D; numbers are not equal to unity
OR E; (the very first entry in the table)
JR NZ, LP_PUW1; work continues
POP HL; remove waste from the stack 0
RET; exit procedures
;
MKUSETB; Create a table of degrees with the base in A
LD HL, USE_TBL; address to create tables
LD DE, # 0001; initialization counter extent
LP_MUT1 LD (HL), E; record of current
INC HL; the degree of
LD (HL), D; to the table and the transition
INC HL; to its next cell
PUSH HL; store address on the stack
LD B, A; founded th degree - "in the loop counter
LD HL, # 0000 reset result
LP_MUT2 ADD HL, DE; calculate results
JR C, GO_MUT; if HL> 65535, is interrupted by
DJNZ LP_MUT2; repeat on the stack
HL_PRW LD HL, _NULL; address of the next character in the table
DB # DD; working with half of the register IX
DEC L; DEC XL - decrement the counter of characters
JR NZ, LP_PRW1; twist cycle, while there are still signs
POP HL; removed unneeded already zero from the stack
RET; exit procedures
;
RIM_TBL; Table significance of the letters in the writing of
Roman numerals
DW 1000
DB "M"; M = 1000; CM = 900
DW 500
DB "D"; D = 500; CD = 400
DW 100
DB "C"; C = 100; XC = 90
DW 1950
DB "L"; L = 50; XL = 40
DW 1910
DB "X"; X = 10; IX = 9
DW 5
DB "V"; V = 5; IV = 4
DW 1
DB "I"; I = 1;-nop;
; --- End of PDES LIB - 2
*
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