Use the cc65 library's new vpoke() function in C demoes.

[greg-king5]

Note that the number and order of vpoke()'s parameters changed.

The VERA address now is a single argument. That makes it slightly easier to see where things are being poked.

[mist64]

Why does vpoke() have the value as the first and the address as the second argument?

[greg-king5]

Why does vpoke() have the value as the first and the address as the second argument?

It allows the implementation to be smaller -- and, both the function and calling programs run faster.
cc65/cc65#934 (comment)

[mobluse]

This order of arguments of vpoke also goes against the ordinary C convention of order dest, src. See e.g. https://www.tutorialspoint.com/c_standard_library/c_function_strcpy.htm

One could change the name of vpoke to e.g. __vpoke and have a macro vpoke with the arguments in the normal order. This would also help people transitioning from BASIC to C.

[greg-king5]

There is precedence for the order that I chose:

int fputc(int c, FILE* f);
int fputs(const char* s, FILE* f);
size_t fwrite(const void* buf, size_t size, size_t count, FILE* f);

Some standard functions use the source, destination order.

[greg-king5]

One could change the name of vpoke() to, e.g., __vpoke(), and have a macro vpoke() with the arguments in the normal order. That also would help people transitioning from BASIC to C.

We already can do it:

#define VPOKE(dest,src) vpoke(src,dest)

We even can go "overboard", and write:

#define VPOKE(high,address,data) vpoke(data, ((unsigned long)(high) << 16) | (address))

[mobluse]

I think those examples of reverse order assignment are exceptions because they were afterthoughts, e.g. putchar() probably existed first, and fputc() came as an extension. I don't think the solution with capitals looks like C. conio.h also has macros for textcolor() etc.

Another example from C library with order destination, source:
void * memcpy ( void * destination, const void * source, size_t num );

[mist64]

I really like the idea of a macro vpoke() with the "correct" order, and an implementation __vpoke() with the swapped one. (Where would we change this?)

[mobluse]

vpoke is defined here:
https://github.com/cc65/cc65/blob/master/include/cx16.h#L190-L193

Then one could change the asm source at:
https://github.com/cc65/cc65/blob/master/libsrc/cx16/vpoke.s

Note: the standard PEEK and POKE in cc65 are in all caps and are macros: https://github.com/cc65/cc65/blob/master/include/peekpoke.h
but that's because ordinary PEEK and POKE are not needed in C. They exist only for BASIC programmers learning C.