use nifty variable argument count trick

+ Found it in newlib. This allows the compiler to more effectively
  optimize away unnecessary register operations. Applied to both kernel
  and init.c for a slight speed increase.

  I really should move init.c to some other repository though, the
  binary files are starting to get annoying

1 files changed, 7 insertions, 7 deletions

diff --git a/arch/riscv64/kernel/proc.c b/arch/riscv64/kernel/proc.c
index 2cc3f36..a7721e2 100644
--- a/arch/riscv64/kernel/proc.c
+++ b/arch/riscv64/kernel/proc.c
@@ -35,15 +35,15 @@ void run_init(struct tcb *t, void *fdt)
 	unreachable();
 }
 
-void set_args(struct tcb *t, struct sys_ret a)
+void set_args(struct tcb *t, size_t n, struct sys_ret a)
 {
 	struct riscv_regs *r = (struct riscv_regs *)(t->regs) - 1;
-	r->a0 = a.s;
-	r->a1 = a.ar0;
-	r->a2 = a.ar1;
-	r->a3 = a.ar2;
-	r->a4 = a.ar3;
-	r->a5 = a.ar4;
+	if (n >= 1) r->a0 = a.s;
+	if (n >= 2) r->a1 = a.ar0;
+	if (n >= 3) r->a2 = a.ar1;
+	if (n >= 4) r->a3 = a.ar2;
+	if (n >= 5) r->a4 = a.ar3;
+	if (n >= 6) r->a5 = a.ar4;
 }
 
 struct sys_ret get_args(struct tcb *t)