Implement draft of new calling convention

Here is the new syscall ABI:

  syscall number in a7
  args in a0 - a6
  return value in a0

Here is the integer register map:

  x0  -> x0
  x1  -> ra
  x2  -> sp
  x3  -> tp
  x4  -> gp
  x5  -> t0
  x6  -> t1
  x7  -> t2
  x8  -> s0
  x9  -> s1
  x10 -> a0
  x11 -> a1
  x12 -> a2
  x13 -> a3
  x14 -> a4
  x15 -> a5
  x16 -> a6
  x17 -> a7
  x18 -> s2
  x19 -> s3
  x20 -> s4
  x21 -> s5
  x22 -> s6
  x23 -> s7
  x24 -> s8
  x25 -> s9
  x26 -> s10
  x27 -> s11
  x28 -> t3
  x29 -> t4
  x30 -> t5
  x31 -> t6

1 files changed, 2 insertions, 2 deletions

diff --git a/pk/handlers.c b/pk/handlers.c
index 2d5356a..2b5bf22 100644
--- a/pk/handlers.c
+++ b/pk/handlers.c
@@ -112,8 +112,8 @@ void handle_fault_store(trapframe_t* tf)
 
 static void handle_syscall(trapframe_t* tf)
 {
-  tf->gpr[16] = do_syscall(tf->gpr[18], tf->gpr[19], tf->gpr[20], tf->gpr[21],
-                           tf->gpr[22], tf->gpr[23], tf->gpr[16]);
+  tf->gpr[10] = do_syscall(tf->gpr[10], tf->gpr[11], tf->gpr[12], tf->gpr[13],
+                           tf->gpr[14], tf->gpr[15], tf->gpr[17]);
   tf->epc += 4;
 }