mirror of
https://github.com/RevCurtisP/C02.git
synced 2024-11-27 19:49:41 +00:00
106 lines
4.6 KiB
Plaintext
106 lines
4.6 KiB
Plaintext
Memory File I/O Functions
|
|
|
|
This library contains functions that mimic file input/ouput operations,
|
|
but read and write directly to RAM. It is intended to allow for the
|
|
design of programs using these functions even on systems that do not
|
|
include any sort of filesystem support, but do allow blocks of memory
|
|
to be loaded from and saved to external storage. For this reason, each
|
|
function has the same signature it's equivalent in the file library.
|
|
|
|
At the beginning of the program use the directives
|
|
|
|
#include <stddef.h02>
|
|
#include <memio.h02>
|
|
|
|
The following functions are defined:
|
|
|
|
m = mopen(z, &a); Open memory file, using zero-page bytes z and z+1
|
|
as a pointer and a as the starting address of the
|
|
file. The starting address must be at least $0100.
|
|
|
|
Returns the the z as the "file pointer", or 0 if an
|
|
invalid address is specified.
|
|
|
|
r = mclose(m); Close memory file pointed to by m, by writing an
|
|
EOF and clearing the memory pointer.
|
|
|
|
Returns 0 if successful or 255 if m contains an
|
|
invalid address.
|
|
|
|
Note: Calls mflush() then sets the bytes at`m and
|
|
m+1 to 0.
|
|
|
|
r = mflush(m); Flush memory file pointed to by m, by writing a
|
|
NUL character at the memory pointer to 0.
|
|
|
|
Returns 0 if successful or 255 if m contains an
|
|
invalid address.
|
|
|
|
Note: The NUL character (ASCII code 0) is use as the
|
|
EOF marker because many systems initialize RAM to 0,
|
|
it's the easiest character to test for, and it can
|
|
never be part of a C style string.
|
|
|
|
c = mgetc(m); Read character from memory file pointed to by m.
|
|
|
|
Returns character read from file.
|
|
|
|
Note: Returns 255 if m contains an invalid address.
|
|
|
|
Returns a system dependent garbage character if end
|
|
of file has been reached or any other I/O error. Use
|
|
meof(f) and merror(f) to check for these conditions.
|
|
|
|
r = mputc(m, c); Write character c to memory file opened to m.
|
|
|
|
Returns 0 if successful or 255 if m contains an
|
|
invalid address.
|
|
|
|
n, c = mgets(m, &s); Reads a maximum of 128 characters from keyboard until
|
|
a newline or EOF character is encountered, storing the
|
|
entered characters as null-terminated string s.
|
|
|
|
Returns number of characters entered ( 255 if m
|
|
contains an invalid address) and the final character
|
|
of the returned atring.
|
|
|
|
Note: Any ASCII control character between EOF (code 0)
|
|
and Space (code 32) is interpreted as a newline. This
|
|
character will be included as the last character of
|
|
the string.
|
|
|
|
n, c = mputs(m, &s): Writes up to 128 characters of null-terminated string
|
|
s to the memory file. Does not write a trailing C/R.
|
|
|
|
Returns number of characters written, or 255 if m
|
|
contains an invalid address.
|
|
|
|
r = mputln(m, &s): Writes up to 128 characters of null-terminated string
|
|
s followed by a C/R to the memory file.
|
|
|
|
Returns 0 if successful or 255 if m contains an
|
|
invalid address.
|
|
|
|
Note: Calls mputs() followed by mputc().
|
|
|
|
l, h = maddr(m); Returns the address contained in memory pointer m
|
|
as two bytes in LSB, MSB format.
|
|
|
|
This non-standard function is included for debugging
|
|
purposes.
|
|
|
|
Note: This library expects the following functions to be defined:
|
|
|
|
setdst(&s); Set destination string pointer
|
|
setsrc(&s); Set source string pointer and initialize index
|
|
|
|
along with the zero page variable pairs
|
|
|
|
dstlo,dsthi: Destination string pointer
|
|
srclo,srchi: Source string pointer
|
|
|
|
and the assembler constant
|
|
|
|
EOFCHR End of File character code`
|
|
RTNCHR Carriage Return character code
|