From d8a80cb31fd8a7a0e6e07df7d5a6aeff6609507e Mon Sep 17 00:00:00 2001
From: Patrick Walton <pcwalton@mimiga.net>
Date: Wed, 28 Sep 2011 12:26:36 -0700
Subject: rt: Add a call stub that switches to the C stack, untested as of yet

---
 src/rt/arch/i386/ccall.S   | 14 ++++++++++++++
 src/rt/arch/i386/context.h |  1 +
 2 files changed, 15 insertions(+)
 create mode 100644 src/rt/arch/i386/ccall.S

(limited to 'src/rt/arch')

diff --git a/src/rt/arch/i386/ccall.S b/src/rt/arch/i386/ccall.S
new file mode 100644
index 00000000000..7adecc4c5d2
--- /dev/null
+++ b/src/rt/arch/i386/ccall.S
@@ -0,0 +1,14 @@
+    .text
+
+// upcall_call_c_stack(void (*fn)(), void *new_esp)
+.globl _upcall_call_c_stack
+_upcall_call_c_stack:
+    movl %esp,%ecx          // grab esp
+    movl 8(%esp),%eax       // save fn
+    movl 12(%esp),%esp      // switch stack
+    pushl %ecx              // save esp on stack
+    calll *%eax
+    popl %esp               // restore esp
+    ret
+
+
diff --git a/src/rt/arch/i386/context.h b/src/rt/arch/i386/context.h
index a31b4c48d14..9a225b79606 100644
--- a/src/rt/arch/i386/context.h
+++ b/src/rt/arch/i386/context.h
@@ -37,6 +37,7 @@ public:
 
   void swap(context &out);
   void call(void *f, void *arg, void *sp);
+  void call(void *f, void *sp);
 
   // Note that this doesn't actually adjust esp. Instead, we adjust esp when
   // we actually do the call. This is needed for exception safety -- if the
-- 
cgit 1.4.1-3-g733a5