1 files changed, 43 insertions, 0 deletions
diff --git a/libgloss/m68k/atari/atari-lseek.c b/libgloss/m68k/atari/atari-lseek.c
new file mode 100644
index 0000000..fa70325
--- /dev/null
+++ b/libgloss/m68k/atari/atari-lseek.c
@@ -0,0 +1,43 @@
+/*
+	Copyright (C) 2025 Mikael Hildenborg
+	SPDX-License-Identifier: BSD-2-Clause
+*/
+
+#include <unistd.h>
+#include <_ansi.h>
+#include "atari-gem_errno.h"
+#include "atari-traps.h"
+
+off_t lseek(int fd, off_t offset, int whence)
+{
+	int newoff = GEM_EIHNDL;
+	if (fd >= 0 && fd <= 2)
+	{
+		// stdin, stdout and stderr just returns OK without doing anything.
+		return 0;
+	}
+	else if (fd >= 3)
+	{
+		// Any file descriptor
+		unsigned short bios_mode = 3; // invalid mode
+		switch (whence)
+		{
+		case SEEK_SET:
+			bios_mode = 0;
+			break;
+		case SEEK_CUR:
+			bios_mode = 1;
+			break;
+		case SEEK_END:
+			bios_mode = 2;
+			break;
+		}
+		newoff = trap1_42((unsigned int)offset, (unsigned short)fd, bios_mode);
+	}
+	if (newoff < 0)
+	{
+		gem_error_to_errno(newoff);
+		return (off_t)-1;
+	}
+	return (off_t)newoff;
+}