diff --git a/Documentation/NuttX.html b/Documentation/NuttX.html
index 117afd5f8f1..bf638b5ec84 100644
--- a/Documentation/NuttX.html
+++ b/Documentation/NuttX.html
@@ -2159,6 +2159,16 @@ pascal-2.1 2011-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr>
buildroot-1.10 2011-xx-xx
+ * Add patch submitted by Dimiter Georgiev to work around problems in building
+ GDB 6.8 with versions of Cygwin > 1.7.
+ * configs/i486-defconfig-4.3.3 - Builds an i486 cross development toolchain
+ using gcc 4.3.3. Why wouldyou want such a thing? On Linux, of course,
+ such a thing is not needed because you can use the installed GCC to build
+ i486 ELF binaries. But that will not work under Cygwin! The Cygwin
+ toolchain (and probably MinGW), build DOS MZ format executables (i.e.,
+ .exe files). That is probably not usable for most NuttX targets.
+ Instead, you should use this i486-elf-gcc to generate true ELF binaries
+ under Cygwin.
diff --git a/arch/x86/src/qemu/qemu_fullcontextrestore.S b/arch/x86/src/qemu/qemu_fullcontextrestore.S
index b4704f23aa8..b9c553fdfe8 100644
--- a/arch/x86/src/qemu/qemu_fullcontextrestore.S
+++ b/arch/x86/src/qemu/qemu_fullcontextrestore.S
@@ -111,34 +111,34 @@ SYMBOL(up_fullcontextrestore):
* stack pointer.
*/
- movl (REG_SP)(%eax), %esp
+ movl (4*REG_SP)(%eax), %esp
/* Save the return address, EFLAGS, and the values as well the
* values of EBX and EAC on the new stack.
*/
- movl (REG_EIP)(%eax), %ebx
+ movl (4*REG_EIP)(%eax), %ebx
push %ebx
- movl (REG_EFLAGS)(%eax), %ebx
+ movl (4*REG_EFLAGS)(%eax), %ebx
push %ebx
- movl (REG_EAX)(%eax), %ebx
+ movl (4*REG_EAX)(%eax), %ebx
push %ebx
- movl (REG_EBX)(%eax), %ebx
+ movl (4*REG_EBX)(%eax), %ebx
push %ebx
/* Now restore the remaining registers */
- movl (REG_EDI)(%ebx), %edi
- movl (REG_ESI)(%ebx), %esi
- movl (REG_EBP)(%ebx), %ebp
- movl (REG_EDX)(%ebx), %edx
- movl (REG_ECX)(%ebx), %ecx
+ movl (4*REG_EDI)(%ebx), %edi
+ movl (4*REG_ESI)(%ebx), %esi
+ movl (4*REG_EBP)(%ebx), %ebp
+ movl (4*REG_EDX)(%ebx), %edx
+ movl (4*REG_ECX)(%ebx), %ecx
/* Restore the segment registers */
- mov (REG_DS)(%ebx), %ds
- mov (REG_CS)(%ebx), %cs
- mov (REG_SS)(%ebx), %ss
+ mov (4*REG_DS)(%ebx), %ds
+ mov (4*REG_CS)(%ebx), %cs
+ mov (4*REG_SS)(%ebx), %ss
/* Restore the correct value of EAX, EBX, and the EFLAGS then return */
diff --git a/arch/x86/src/qemu/qemu_saveusercontext.S b/arch/x86/src/qemu/qemu_saveusercontext.S
index 841023b40a4..3da2d149131 100644
--- a/arch/x86/src/qemu/qemu_saveusercontext.S
+++ b/arch/x86/src/qemu/qemu_saveusercontext.S
@@ -121,37 +121,37 @@ SYMBOL(up_saveusercontext):
* because it will be the return value from this function.
*/
- movl %ebx, (REG_EBX)(%eax)
- movl %esi, (REG_ESI)(%eax)
- movl %edi, (REG_EDI)(%eax)
+ movl %ebx, (4*REG_EBX)(%eax)
+ movl %esi, (4*REG_ESI)(%eax)
+ movl %edi, (4*REG_EDI)(%eax)
/* Save the segment registers */
- mov %ss, (REG_SS)(%eax)
- mov %cs, (REG_CS)(%eax)
- mov %ds, (REG_DS)(%eax)
+ mov %ss, (4*REG_SS)(%eax)
+ mov %cs, (4*REG_CS)(%eax)
+ mov %ds, (4*REG_DS)(%eax)
/* Save the value of SP as will be after we return (don't bother to save
* REG_ESP).
*/
leal 4(%esp), %ecx
- movl %ecx, (REG_SP)(%eax)
+ movl %ecx, (4*REG_SP)(%eax)
/* Fetch the PC from the stack and save it in the save block */
movl 0(%esp), %ecx
- movl %ecx, (REG_EIP)(%eax)
+ movl %ecx, (4*REG_EIP)(%eax)
/* Save the framepointer */
- movl %ebp, (REG_EBP)(%eax)
+ movl %ebp, (4*REG_EBP)(%eax)
/* Get and save the interrupt state */
pushf
pop %ecx
- movl %ecx, (REG_EFLAGS)(%eax)
+ movl %ecx, (4*REG_EFLAGS)(%eax)
/* And return 0. 'ret' will remove the EIP from the top of the stack. */
diff --git a/configs/qemu-i486/README.txt b/configs/qemu-i486/README.txt
index 32cbfa76f44..9d5a49c1456 100644
--- a/configs/qemu-i486/README.txt
+++ b/configs/qemu-i486/README.txt
@@ -8,6 +8,7 @@ Contents
^^^^^^^^
* QEMU
+ * Toolchains
* Configurations
QEMU
@@ -51,6 +52,57 @@ Cygwin build problems:
binaries. I found 0.14.0 here: http://dietpc.org/windows/qemu/, or
2. Try building QEMU with MingGW
+Toolchains
+^^^^^^^^^^
+
+ Two target environments are supported: (1) Linux and (2) Cygwin under Windows.
+ Any GCC toolchain that can produce i486 ELF binaries should work. On Linux,
+ you can probably use the installed system gcc. But that will not work with
+ Cygwin. Why? Because the Cygwin gcc (and probably the MinGW gcc as well) do
+ not produce ELF final binaries but, rather, DOS MZ executables (i.e., .exe
+ files). Those cannot be used with QEMU.
+
+ The file */setenv.sh should be modified to point to the correct path to the
+ GCC toolchain (if different from the default in your PATH variable).
+
+ Cygwin Buildroot Toolchain
+
+ With Cygwin the solution is to build an i486 cross-development toolchain to
+ generate the i486 ELF files needed by QEMU. The NuttX buildroot package will
+ create such a toolchain.
+
+ NOTE: As of this writing, none of the released buildroot packages support the
+ i486 build. This is only available in SVN or in any any 1.10 or later buildroot
+ release.
+
+ Buildroot Instructions
+
+ 1. You must have already configured Nuttx in /nuttx.
+
+ cd tools
+ ./configure.sh qemu-i486/
+
+ 2. Download the latest buildroot package into
+
+ 3. unpack the buildroot tarball. The resulting directory may
+ have versioning information on it like buildroot-x.y.z. If so,
+ rename /buildroot-x.y.z to /buildroot.
+
+ 4. cd /buildroot
+
+ 5. cp configs/i486-defconfig-4.3.3 .config
+
+ 6. make oldconfig
+
+ 7. make
+
+ 8. Edit setenv.h, if necessary, so that the PATH variable includes
+ the path to the newly built binaries.
+
+ See the file configs/README.txt in the buildroot source tree. That has more
+ detailed PLUS some special instructions that you will need to follow if you
+ run into problems building the toolchain for Cygwin under Windows.
+
Configurations
^^^^^^^^^^^^^^
diff --git a/configs/qemu-i486/ostest/ld.script b/configs/qemu-i486/ostest/ld.script
index cf4e40cb0ce..612160e41f0 100755
--- a/configs/qemu-i486/ostest/ld.script
+++ b/configs/qemu-i486/ostest/ld.script
@@ -33,6 +33,7 @@
*
****************************************************************************/
+OUTPUT_ARCH(elf_i386)
ENTRY(__start)
SECTIONS
{