uint32_t cs_bounce_size;
} __com32;
+/*
+ * These functions convert between linear pointers in the range
+ * 0..0xFFFFF and real-mode style SEG:OFFS pointers. Note that a
+ * 32-bit linear pointer is not compatible with a SEG:OFFS pointer
+ * stored in two consecutive 16-bit words.
+ */
+static inline uint16_t SEG(void *__p)
+{
+ return (uint16_t)(((uint32_t)__p) >> 4);
+}
+
+static inline uint16_t OFFS(void *__p)
+{
+ /* The double cast here is to shut up gcc */
+ return (uint16_t)(uint32_t)__p & 0x000F;
+}
+
+static inline void *MK_PTR(uint16_t __seg, uint16_t __offs)
+{
+ return (void *)( ((uint32_t)__seg << 4) + (uint32_t)__offs );
+}
+
#endif /* _COM32_H */
--- /dev/null
+#ident "$Id$"
+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright 2002 H. Peter Anvin - All Rights Reserved
+ *
+ * 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., 53 Temple Place Ste 330,
+ * Bostom MA 02111-1307, USA; either version 2 of the License, or
+ * (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * hello2.c
+ *
+ * Simple COM32 image
+ *
+ * This version shows how to use the bounce buffer for data transfer
+ * to the BIOS or COMBOOT system calls.
+ */
+
+#include <com32.h>
+
+#define NULL ((void *)0)
+
+static inline void memset(void *buf, int ch, unsigned int len)
+{
+ asm volatile("cld; rep; stosb"
+ : "+D" (buf), "+c" (len) : "a" (ch) : "memory");
+}
+
+static inline void memcpy(void *dst, const void *src, unsigned int len)
+{
+ asm volatile("cld; rep; movsb"
+ : "+D" (dst), "+S" (src), "+c" (len) : : "memory");
+}
+
+int __start(void)
+{
+ const char msg[] = "Hello, World!\r\n";
+ com32sys_t inreg, outreg;
+ const char *p;
+
+ memset(&inreg, 0, sizeof inreg);
+
+ /* Bounce buffer is at least 64K in size */
+ memcpy(__com32.cs_bounce, msg, sizeof msg);
+ inreg.eax.w[0] = 0x0002; /* Write string */
+ inreg.ebx.w[0] = OFFS(__com32.cs_bounce);
+ inreg.es = SEG(__com32.cs_bounce);
+ __com32.cs_syscall(0x22, &inreg, NULL);
+
+ return 0;
+}