Rewrite access in terms of get-byte

- This changes happens to slow down the whole system a lot.
Also add a test for the PC.

1 files changed, 16 insertions, 6 deletions

diff --git a/bytepusher.scm b/bytepusher.scm
index 9c8b96b..7e08e2b 100644
--- a/bytepusher.scm
+++ b/bytepusher.scm
@@ -40,9 +40,7 @@
 ;; memory ----
 
 (define (get-pc)
-  (+ (ash (get-byte 4)  0)
-     (ash (get-byte 3)  8)
-     (ash (get-byte 2) 16)))
+  (get-addr 2))
 
 (define (set-pc! value)
   (set-byte! 4 (ash value 0))
@@ -50,11 +48,12 @@
   (set-byte! 2 (ash value -16)))
 
 (define (get-addr pos)
-  (+ (bytevector-u16-ref memory (+ 1 pos) (endianness big))
-     (ash (bytevector-u8-ref memory pos) 16)))
+  (+ (ash (get-byte (+ 2 pos))  0)
+     (ash (get-byte (+ 1 pos))  8)
+     (ash (get-byte      pos)  16)))
 
 (define (get-initial-pixel)
-  (ash (bytevector-u8-ref memory 5) 16))
+  (ash (get-byte 5) 16))
 
 (define (get-sample)
   (bytevector-u16-ref memory 6 (endianness big)))
@@ -204,3 +203,14 @@
   (sdl-quit))
 
 ;; ---- main operation
+
+
+;; tests ----
+(define (test-pc)
+  (for-each
+    (lambda (addr)
+      (set-pc! addr)
+      (when (not (= (get-pc) addr))
+        (error "Error in set pc")))
+    (iota #x1000000)))
+;; ---- tests