plat/msdos86: add gettimeofday( )

plat/msdos86/include/ack/plat.h

@@ -7,6 +7,5 @@
 #define _ACK_PLAT_H
 
 #define ACKCONF_WANT_O_TEXT_O_BINARY 1
-#define ACKCONF_WANT_EMULATED_TIME 0
 
 #endif

plat/msdos86/libsys/gettimeofday.c

@@ -0,0 +1,92 @@
+/* $Source$
+ * $State$
+ * $Revision$
+ */
+
+/*
+ * Derived from dos-gettimeofday.c for newlib-ia16 which was written for the
+ * gcc-ia16 toolchain.
+ *
+ * Copyright (c) 2017--2021 TK Chia
+ *
+ * The authors hereby grant permission to use, copy, modify, distribute,
+ * and license this software and its documentation for any purpose, provided
+ * that existing copyright notices are retained in all copies and that this
+ * notice is included verbatim in any distributions. No written agreement,
+ * license, or royalty fee is required for any of the authorized uses.
+ * Modifications to this software may be copyrighted by their authors
+ * and need not follow the licensing terms described here, provided that
+ * the new terms are clearly indicated on the first page of each file where
+ * they apply.
+ */
+
+#include <string.h>
+#include <unistd.h>
+#include <time.h>
+#include <stdbool.h>
+#include "libsys.h"
+
+extern long _timezone;
+extern int _daylight;
+
+int gettimeofday(struct timeval *tv, struct timezone *tz)
+{
+	static volatile bool tzinited = false;
+	struct _dosdate dosdt, olddt;
+	struct _dostime dostm;
+	suseconds_t usec;
+	struct tm tm;
+	time_t tim;
+
+	if (!tzinited)
+	{
+		tzset();
+		tzinited = true;
+	}
+
+	memset(&tm, 0, sizeof tm);
+
+	_sys_getdate(&dosdt);
+	do
+	{
+		uint8_t hour;
+
+		_sys_gettime(&dostm);
+		tm.tm_hour = hour = dostm.hour;
+		tm.tm_min = dostm.minute;
+		tm.tm_sec = dostm.second;
+		usec = dostm.hsecond * 10000UL;
+
+		/* If the time is close to midnight, read the date again to
+		 * check for midnight crossover.  If crossover happens,
+		 * repeat until it stops. */
+		if (hour)
+			break;
+
+		olddt = dosdt;
+		_sys_getdate(&dosdt);
+	} while (dosdt.day != olddt.day);
+
+	tm.tm_year = dosdt.year - 1900;
+	tm.tm_mon = dosdt.month - 1;
+	tm.tm_mday = dosdt.day;
+	tm.tm_isdst = -1;
+
+	tim = mktime(&tm);
+	if (tim == -1)
+		return -1;
+
+	if (tv)
+	{
+		tv->tv_sec = tim;
+		tv->tv_usec = usec;
+	}
+
+	if (tz)
+	{
+		tz->tz_minuteswest = _timezone / 60;
+		tz->tz_dsttime = _daylight;
+	}
+
+	return 0;
+}

plat/msdos86/libsys/libsys.h

@@ -41,6 +41,21 @@ extern struct _fdmodes _sys_fdmodes;
 
 #define _FDVECMASK (sizeof(_fdvec_t) * CHAR_BIT - 1)
 
+/* Structures for getting MS-DOS's idea of the current date and time. */
+
+struct _dosdate {
+	uint8_t day;
+	uint8_t month;
+	uint16_t year;
+};
+
+struct _dostime {
+	uint8_t minute;
+	uint8_t hour;
+	uint8_t hsecond;
+	uint8_t second;
+};
+
 extern int _sys_getmode(int);
 extern int _sys_setmode(int, int);
 extern int _sys_iseof(int);
@@ -53,6 +68,7 @@ extern int _sys_exists(const char *);
 extern int _sys_rawcreat(const char *, unsigned);
 extern int _sys_rawopen(const char *, int);
 extern off_t _sys_rawlseek(int, off_t, int);
-
+extern void _sys_getdate(struct _dosdate *);
+extern void _sys_gettime(struct _dostime *);
 
 #endif

plat/msdos86/libsys/sys_getdate.s

@@ -0,0 +1,25 @@
+#
+! $Source$
+! $State$
+! $Revision$
+
+! Declare segments (the order is important).
+
+.sect .text
+.sect .rom
+.sect .data
+.sect .bss
+
+.sect .text
+
+! Get the current system date from MS-DOS.
+
+.define __sys_getdate
+__sys_getdate:
+	movb ah, 0x2a
+	int 0x21
+	mov bx, sp
+	mov bx, 2(bx)
+	mov (bx), dx
+	mov 2(bx), cx
+	ret

plat/msdos86/libsys/sys_gettime.s

@@ -0,0 +1,25 @@
+#
+! $Source$
+! $State$
+! $Revision$
+
+! Declare segments (the order is important).
+
+.sect .text
+.sect .rom
+.sect .data
+.sect .bss
+
+.sect .text
+
+! Get the current system time from MS-DOS.
+
+.define __sys_gettime
+__sys_gettime:
+	movb ah, 0x2c
+	int 0x21
+	mov bx, sp
+	mov bx, 2(bx)
+	mov (bx), cx
+	mov 2(bx), dx
+	ret