Add second hello world sample

4 files changed, 78 insertions, 2 deletions

diff --git a/com32/include/com32.h b/com32/include/com32.h
index a56cc698..c080ce7f 100644
--- a/com32/include/com32.h
+++ b/com32/include/com32.h
@@ -54,4 +54,26 @@ extern struct com32_sys_args {
   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 */
diff --git a/sample/Makefile b/sample/Makefile
index 54fdb097..5626d131 100644
--- a/sample/Makefile
+++ b/sample/Makefile
@@ -25,7 +25,7 @@ PPMTOLSS16 = 	../ppmtolss16
 
 .SUFFIXES: .lss .c .o .elf .c32
 
-all: syslogo.lss hello.c32
+all: syslogo.lss hello.c32 hello2.c32
 
 %.o: %.S
 	$(CC) $(SFLAGS) -c -o $@ $<
diff --git a/sample/hello2.c b/sample/hello2.c
new file mode 100644
index 00000000..68dc6976
--- /dev/null
+++ b/sample/hello2.c
@@ -0,0 +1,55 @@
+#ident "$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;
+}
diff --git a/writestr.inc b/writestr.inc
index 8b614cdf..a0d14714 100644
--- a/writestr.inc
+++ b/writestr.inc
@@ -40,4 +40,3 @@ cwritestr:
 .end:		popad
 		popfd
                 ret
-