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C02/include/old/header.txt
2018-01-28 13:30:49 -05:00

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System Specific Header File Specification
The very first directive of the program must be
#include <header.h02>
where header.h02 is the system specific header file, (e.g. apple1.h02,
vic20.h02, etc.).
Note: This will probably be replaced with a command line parameter
(e.g. '-s apple1', '-s vic20', etc...) to allow program portability.
For compatability with the C02 Standard Library, the following functions
must be defined
c = plkey(); Polls keyboard and returns raw ASCII character
corresponding to last/current pressed key.
Returns constant NULKEY (usually 0) if no key was
pressed.
c = rdkey(); Waits for a keypress and returns the raw ASCII
character corresponding to the pressed key.
Note: Usually a loop that calls plkey(), but may
also directly call a system subroutine.
c = getkey(); Waits for a keypress and returns the cleaned
ASCII value corresponding to the pressed key.
Note: Calls rdkey() followed by any necessary
character code conversions. This can be due to
high-bit being set by keyboard decoder,
non-standard key mappings, keys that generate
escape sequences, etc...
newlin(); Advances the cursor to the beginning of then
next line.
Note: Depending on the system, this will usually
output a Carriage Return, Line Feed, both.
prchr(c); Writes character c to the screen.
Note: May directly access memory-mapped I/O
or may call a system subroutine.
r = getstr(&s); Reads a maximum of 128 characters from keyboard
until a carriage return is received, storing the
entered characters as null-terminated string s.
Allows corrections using Backspace/Delete.
Pressing the Escape/Abort key terminates entry,
leaving the string in an undefined state.
Returns number of characters entered, or 255
if entry was aborted.
r = outstr(n, &s): Writes up to 128 characters of null-terminated
string s to the screen, starting at position n.
Returns position of null terminator in string.
r = putstr(&s): Writes up to 128 characters of null-terminated
string s to the screen and advances the cursor to
the beginning of the next line.
Returns number of characters printed.
Note: Calls putstr(0, &s) followed by newlin().
along with the Zero Page locations (each pair of which must be sequential)
strlo, strhi String Pointer for stdio.asm and string.asm
srclo, rcshi Secondary String Pointer for string.asm
the following locations that may be Zero Page, but don't have to before
temp0, temp1 Temporary variables used by stdlib.asm
and the following locations that must be preserved between function calls
random Storage for the Random Number Generator
Contains the last number generated and is used to
generate the next number in the sequence
rdseed Seed for Pseudo-Random Number Generator
Usually a counter or timer. If one is not provided
by the system, should be generated by incrementing
in the plkey(), rdkey() functions.
and the constants
DELKEY ASCII code for Delete/Backspace key (usually DEL or BS)
ESCKEY ASCII code for Escape/Abort key (usually ESC)
NULKEY Returned if no Key was Pressed
RTNKEY ASCII code for Return/Enter key (usually CR)