rvinterf/etmsync/fsnew.c: cast 0 to (char *) for execl sentinel I generally don't use NULL and use plain 0 instead, based on a "NULL considered harmful" discussion on the classiccmp mailing list many aeons ago (I couldn't find it, and I reason that it must have been 2005 or earlier), but a recent complaint by a packager sent me searching, and I found this: https://ewontfix.com/11/ While I don't give a @#$% about "modern" systems and code-nazi tools, I realized that passing a plain 0 as a pointer sentinel in execl is wrong because it will break on systems where pointers are longer than the plain int type. Again, I don't give a @#$% about the abomination of x86_64 and the like, but if anyone ever manages to port my code to something like a PDP-11 (16-bit int, 32-bit long and pointers), then passing a plain 0 as a function argument where a pointer is expected most definitely won't work: if the most natural stack slot and SP alignment unit is 16 bits, fitting an int, with longs and pointers taking up two such slots, then the call stack will be totally wrong with a plain 0 passed for a pointer. Casting the 0 to (char *) ought to be the most kosher solution for the most retro systems possible.

/*
 * FreeCalypso buzzer "melodies" have times measured in TDMA frames,
 * as that is the time unit in the main firmware which will ultimately
 * play them.  In this standalone buzzer player we simulate TDMA frame
 * timing by programming Calypso TIMER1 with the period of 1875, and
 * we detect timer overflow (one virtual TDMA frame time having passed)
 * by polling the read register to avoid the need for interrupt handling
 * infrastructure.
 */

#include "types.h"
#include "timer.h"

void
timer_init()
{
	TIMER1_REGS.cntl = CNTL_CLOCK_ENABLE;
	TIMER1_REGS.load = 1875;
	TIMER1_REGS.cntl = CNTL_CLOCK_ENABLE | CNTL_AUTO_RELOAD | CNTL_START;
}

void
wait_for_tdma_frame()
{
	u16 read1, read2;

	read1 = TIMER1_REGS.read;
	for (;;) {
		read2 = TIMER1_REGS.read;
		if (read2 > read1)
			return;
		read1 = read2;
	}
}