libthread: context switching for arm, still not complete

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

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;
+}
+
+

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
 

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