Save sp

src/args.S

@@ -1,9 +1,22 @@
-.globl fetch_argc, fetch_argv
+.data
+sp_start:   .space 8
+
+.section .text
+.globl save_sp, fetch_argc, fetch_argv
+
+save_sp:
+    sd sp, sp_start, t0 # save the stack pointer
+    ret
 
 # Fetch argument count
 # @param[in] a0: unused.
 # @param[out] a0: number of arguments.
 fetch_argc:
-    ld a0, 0(sp)
+    ld t0, sp_start # dereference the buffer
+    ld a0, 0(t0) # dereference the address
     ret
-    
+
+# Fetch argument value
+# @param[in] a0: argv[a0].
+# @param[out] a0: address of arg.
+fetch_argv: