1 files changed, 42 insertions, 0 deletions
diff --git a/kernel/swtch.S b/kernel/swtch.S
new file mode 100644
index 0000000..17a8663
--- /dev/null
+++ b/kernel/swtch.S
@@ -0,0 +1,42 @@
+# Context switch
+#
+#   void swtch(struct context *old, struct context *new);
+# 
+# Save current registers in old. Load from new.	
+
+
+.globl swtch
+swtch:
+        sd ra, 0(a0)
+        sd sp, 8(a0)
+        sd s0, 16(a0)
+        sd s1, 24(a0)
+        sd s2, 32(a0)
+        sd s3, 40(a0)
+        sd s4, 48(a0)
+        sd s5, 56(a0)
+        sd s6, 64(a0)
+        sd s7, 72(a0)
+        sd s8, 80(a0)
+        sd s9, 88(a0)
+        sd s10, 96(a0)
+        sd s11, 104(a0)
+
+        ld ra, 0(a1)
+        ld sp, 8(a1)
+        ld s0, 16(a1)
+        ld s1, 24(a1)
+        ld s2, 32(a1)
+        ld s3, 40(a1)
+        ld s4, 48(a1)
+        ld s5, 56(a1)
+        ld s6, 64(a1)
+        ld s7, 72(a1)
+        ld s8, 80(a1)
+        ld s9, 88(a1)
+        ld s10, 96(a1)
+        ld s11, 104(a1)
+        
+        ret
+
+