From ba940ae61c4c33766e385b63ecf49bec25f301d7 Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@swtch.com>
Date: Wed, 18 Nov 2009 04:12:17 -0500
Subject: libthread: context switching for arm, still not complete

---
 src/libthread/Linux-arm-context.s     | 41 +++++++++++++++++++++++++++++++++++
 src/libthread/Linux-arm-swapcontext.c | 26 ++++++++++++++++++++++
 src/libthread/sysofiles.sh            |  7 ++++++
 src/libthread/threadimpl.h            |  8 +++----
 4 files changed, 78 insertions(+), 4 deletions(-)
 create mode 100644 src/libthread/Linux-arm-context.s
 create mode 100644 src/libthread/Linux-arm-swapcontext.c

(limited to 'src/libthread')

diff --git a/src/libthread/Linux-arm-context.s b/src/libthread/Linux-arm-context.s
new file mode 100644
index 00000000..9bd54f8a
--- /dev/null
+++ b/src/libthread/Linux-arm-context.s
@@ -0,0 +1,41 @@
+.globl mygetmcontext
+mygetmcontext:
+	str	r1, [r0,#4]
+	str	r2, [r0,#8]
+	str	r3, [r0,#12]
+	str	r4, [r0,#16]
+	str	r5, [r0,#20]
+	str	r6, [r0,#24]
+	str	r7, [r0,#28]
+	str	r8, [r0,#32]
+	str	r9, [r0,#36]
+	str	r10, [r0,#40]
+	str	r11, [r0,#44]
+	str	r12, [r0,#48]
+	str	r13, [r0,#52]
+	str	r14, [r0,#56]
+	/* store 1 as r0-to-restore */
+	mov	r1, #1
+	str	r1, [r0]
+	/* return 0 */
+	mov	r0, #0
+	mov	pc, lr
+
+.globl mysetmcontext
+mysetmcontext:
+	ldr	r1, [r0,#4]
+	ldr	r2, [r0,#8]
+	ldr	r3, [r0,#12]
+	ldr	r4, [r0,#16]
+	ldr	r5, [r0,#20]
+	ldr	r6, [r0,#24]
+	ldr	r7, [r0,#28]
+	ldr	r8, [r0,#32]
+	ldr	r9, [r0,#36]
+	ldr	r10, [r0,#40]
+	ldr	r11, [r0,#44]
+	ldr	r12, [r0,#48]
+	ldr	r13, [r0,#52]
+	ldr	r14, [r0,#56]
+	ldr	r0, [r0]
+	mov	pc, lr
diff --git a/src/libthread/Linux-arm-swapcontext.c b/src/libthread/Linux-arm-swapcontext.c
new file mode 100644
index 00000000..43358800
--- /dev/null
+++ b/src/libthread/Linux-arm-swapcontext.c
@@ -0,0 +1,26 @@
+#include "threadimpl.h"
+
+void
+makecontext(ucontext_t *uc, void (*fn)(void), int argc, ...)
+{
+        int i, *sp;
+        va_list arg;
+        
+        sp = (int*)uc->uc_stack.ss_sp+uc->uc_stack.ss_size/4;
+        va_start(arg, argc);
+        for(i=0; i<4 && i<argc; i++)
+                uc->uc_mcontext.gregs[i] = va_arg(arg, uint);
+        va_end(arg);
+        uc->uc_mcontext.gregs[13] = (uint)sp;
+        uc->uc_mcontext.gregs[14] = (uint)fn;
+}
+
+int
+swapcontext(ucontext_t *oucp, const ucontext_t *ucp)
+{
+        if(getcontext(oucp) == 0)
+                setcontext(ucp);
+        return 0;
+}
+
+
diff --git a/src/libthread/sysofiles.sh b/src/libthread/sysofiles.sh
index cdc1ad02..27029471 100644
--- a/src/libthread/sysofiles.sh
+++ b/src/libthread/sysofiles.sh
@@ -4,6 +4,9 @@ test -f $PLAN9/config && . $PLAN9/config
 
 tag="$OBJTYPE-$SYSNAME-${SYSVERSION:-`uname -r`}-${CC9:-cc}"
 case "$tag" in
+arm-Linux-*)
+	echo ${SYSNAME}-${OBJTYPE}-asm.o $SYSNAME.o
+	;;	
 *-Linux-2.6.*)
 	echo pthread.o
 	;;
@@ -36,5 +39,9 @@ sparc64-Linux)
 	# so we supply our own copy from the latest glibc.
 	echo Linux-sparc64-context.o Linux-sparc64-swapcontext.o
 	;;
+arm-Linux)
+	# ARM doesn't supply them either.
+	echo Linux-arm-context.o Linux-arm-swapcontext.o
+	;;
 esac
 
diff --git a/src/libthread/threadimpl.h b/src/libthread/threadimpl.h
index 8b00694e..f5c44f63 100644
--- a/src/libthread/threadimpl.h
+++ b/src/libthread/threadimpl.h
@@ -73,10 +73,10 @@ but surely the latter would be defined(__sparc__).
 */
 
 #if defined(__arm__)
-int getmcontext(mcontext_t*);
-void setmcontext(const mcontext_t*);
-#define	setcontext(u)	setmcontext(&(u)->uc_mcontext)
-#define	getcontext(u)	getmcontext(&(u)->uc_mcontext)
+int mygetmcontext(mcontext_t*);
+void mysetmcontext(const mcontext_t*);
+#define	setcontext(u)	mysetmcontext(&(u)->uc_mcontext)
+#define	getcontext(u)	mygetmcontext(&(u)->uc_mcontext)
 #endif
 
 
-- 
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