From 71f30d9fccf71b4c6be7a01a3b47deaa2e5ab3c6 Mon Sep 17 00:00:00 2001
From: hpa <hpa>
Date: Sat, 13 Dec 2003 02:22:56 +0000
Subject: [PATCH] Minor com32 wrapper code cleanup

---
 comboot.doc       |  1 +
 sample/Makefile   |  8 ++++++--
 sample/c32entry.S |  7 +++++--
 sample/c32exit.S  | 10 ++++++++++
 4 files changed, 22 insertions(+), 4 deletions(-)
 create mode 100644 sample/c32exit.S

diff --git a/comboot.doc b/comboot.doc
index 9132bf2..e9327f5 100644
--- a/comboot.doc
+++ b/comboot.doc
@@ -79,6 +79,7 @@ notification to the program how much memory is available.
 The following arguments are passed to the program on the stack:
 
  Address  Size	Meaning
+ [ESP]    dword Return (termination) address
  [ESP+4]  dword	Number of additional arguments (currently 5)
  [ESP+8]  dword	Pointer to the command line arguments (null-terminated string)
  [ESP+12] dword Pointer to INT call helper function
diff --git a/sample/Makefile b/sample/Makefile
index 8964c00..8a2eb6d 100644
--- a/sample/Makefile
+++ b/sample/Makefile
@@ -27,18 +27,22 @@ OBJCOPY    = objcopy
 PPMTOLSS16 = 	../ppmtolss16
 LIB	   = libcom32.a
 
-LIBOBJS	   = conio.o atou.o skipatou.o printf.o
+LIBOBJS	   = conio.o atou.o skipatou.o printf.o c32exit.o
 
 .SUFFIXES: .lss .c .o .elf .c32
 
-all: syslogo.lss comecho.com hello.c32 hello2.c32 filetest.c32 c32echo.c32 fd.c32 chain.c32
+all: syslogo.lss comecho.com hello.c32 hello2.c32 filetest.c32 c32echo.c32 \
+     fd.c32 chain.c32 $(LIB)
 
+.PRECIOUS: %.o
 %.o: %.S
 	$(CC) $(SFLAGS) -c -o $@ $<
 
+.PRECIOUS: %.o
 %.o: %.c
 	$(CC) $(CFLAGS) -c -o $@ $<
 
+.PRECIOUS: %.elf
 %.elf: c32entry.o %.o $(LIB)
 	$(LD) -Ttext 0x101000 -e _start -o $@ $^
 
diff --git a/sample/c32entry.S b/sample/c32entry.S
index 1ae57a2..ee71d8f 100644
--- a/sample/c32entry.S
+++ b/sample/c32entry.S
@@ -47,9 +47,10 @@ _start:
 		rep ; stosl
 
 		# Copy COM32 invocation parameters
-		leal 4(%esp),%esi
+		leal 4(%esp),%esi		# Argument list
 		movl $__com32,%edi
 		movl $6,%ecx
+		movl %esp,-4(%edi)		# Save the initial stack ptr
 		cmpl (%esi),%ecx
 		jbe 1f
 		movl (%esi),%ecx
@@ -60,5 +61,7 @@ _start:
 		jmp __start
 
 		.section ".bss","a"
+		.globl __entry_esp
+__entry_esp:	.space 4
 		.globl __com32
-__com32:	.space 24
+__com32:	.space 4*6
diff --git a/sample/c32exit.S b/sample/c32exit.S
new file mode 100644
index 0000000..5c5ba03
--- /dev/null
+++ b/sample/c32exit.S
@@ -0,0 +1,10 @@
+# $Id#
+#
+# Implementation of exit() for com32 based on c32entry.S
+#
+	.text
+	.globl exit
+exit:
+	movl 4(%esp),%eax		# Exit code in %eax = return value
+	movl (__entry_esp),%esp		# Return stack pointer to entry value
+	ret				# Return to termination address
-- 
2.7.4