1 files changed, 41 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/core/call16.c b/contrib/syslinux-4.02/core/call16.c
new file mode 100644
index 0000000..095f814
--- /dev/null
+++ b/contrib/syslinux-4.02/core/call16.c
@@ -0,0 +1,41 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2009-2010 Intel Corporation; author: H. Peter Anvin
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ *   Boston MA 02110-1301, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * call16.c
+ *
+ * Simple wrapper to call 16-bit core functions from 32-bit code
+ */
+
+#include <stddef.h>
+#include <stdio.h>
+#include "core.h"
+
+const com32sys_t zero_regs;	/* Common all-zero register set */
+
+static inline uint32_t eflags(void)
+{
+    uint32_t v;
+
+    asm volatile("pushfl ; popl %0" : "=rm" (v));
+    return v;
+}
+
+void call16(void (*func)(void), const com32sys_t *ireg, com32sys_t *oreg)
+{
+    com32sys_t xreg = *ireg;
+
+    /* Enable interrupts if and only if they are enabled in the caller */
+    xreg.eflags.l = (xreg.eflags.l & ~EFLAGS_IF) | (eflags() & EFLAGS_IF);
+
+    core_farcall((size_t)func, &xreg, oreg);
+}