# HG changeset patch
# User Robert McIntyre <rlm@mit.edu>
# Date 1331876608 18000
# Node ID 0831da75d2c5fe1bfad293fdec5d2a8db975e8a0
# Parent  6fe33bb5ea221df8f8a485ac32373206a0dd3e96
completed frame-counting machine language program with dylan's help

diff -r 6fe33bb5ea22 -r 0831da75d2c5 clojure/com/aurellem/assembly.clj
--- a/clojure/com/aurellem/assembly.clj	Thu Mar 15 17:29:49 2012 -0500
+++ b/clojure/com/aurellem/assembly.clj	Fri Mar 16 00:43:28 2012 -0500
@@ -74,7 +74,7 @@
                    (binary-str (aget (memory state) mem))))
   state)
 
-(defn read-buttons []
+(defn read-down-button []
   (-> (tick (mid-game))
       (IE! 0) ; disable interrupts
       (inject-item-assembly
@@ -82,7 +82,8 @@
         ;; write 00010000 to 0xFF00 to select joypad
         [0x18   ;D31D                    ; jump over          
          0x01   ;D31E                    ; the next 8 bits
-         (Integer/parseInt "00100000" 2) ;D31F data section 
+                ;D31F
+         (Integer/parseInt "00100000" 2) ; data section 
          
          0xFA   ;D320                    ; load (D31F) into A
          0x1F   ;D321      -->       
@@ -123,8 +124,120 @@
         
         []))))
 
+
+;; specs for main bootstrap program
+;; starts in "mode-select" mode
+;;   Each button press takes place in a single frame.
+;;   mode-select-mode takes one of the main buttons
+;;   which selects one of up to eight modes
+;;   mode 1 activated by the "A" button
+;;   the next two button presses indicates the start
+;;   memory location which to which the bootstrap
+;;   program will write.
+;;   This is done by using each of the eight buttons to
+;;   spell out an 8 bit number.  The order of buttons is
+;;   ["A" "B" "start" "select" "up" "right" "down" "left"],
+;;   [:a :start :l]  -->  10100001
+
+;;   the next button press determines how many bytes are to be
+;;   written, starting at the start position.
+
+;;   then, the actual bytes are entered and are written to the
+;;   start address in sequence.
+
+
+(defn count-frames []
+  (-> (tick (mid-game))
+      (IE! 0) ; disable interrupts
+      (inject-item-assembly
+       ;; write 00010000 to 0xFF00 to select joypad
+       [0x18   ;D31D                    ; jump over          
+        0x02   ;D31E                    ; the next 2 bytes
+        0x00   ;D31F                    ; frame-count
+        0x00   ;D320                    ; v-blank-prev
+        
+        0xFA   ;D321
+        0x41   ;D322                    ; load (FF41) into A
+        0xFF   ;D323                    ; this contains mode flags
+
+
+        
+        ;; if we're in v-blank, the bit-1 is 0
+        ;; and bit-2 is 1  Otherwise, it is not v-blank.
+        0xCB   ;D324                     ; test bit-1 of A
+        0x4F   ;D325                         
+
+        0xC2   ;D326                     ; if bit-1 is not 0
+        0x43   ;D327                     ; GOTO not-v-blank
+        0xD3   ;D328
+        
+        0xCB   ;D329                     ; test bit-0 of A 
+        0x47   ;D32A
+
+        0xCA   ;D32B                     ; if bit-0 is not 1
+        0x43   ;D32C                     ; GOTO not-v-blank
+        0xD3   ;D32D
+        
+        ;; in v-blank mode
+
+           ;; if v-blank-prev was 0,
+           ;; increment frame-count
+
+        0xFA   ;D32E                    ; load v-blank-prev to A
+        0x20   ;D32F
+        0xD3   ;D330
+        
+        0xCB   ;D331
+        0x47   ;D332                    ; test bit-0 of A 
+
+        0x20   ;D333                    ; skip next section
+        0x07   ;D334                    ; if v-blank-prev was not zero 
+        
+           ;; v-blank was 0, increment frame-count
+        0xFA   ;D335                    ; load frame-count into A
+        0x1F   ;D336
+        0xD3   ;D337                   
+
+        0x3C   ;D338                    ; inc A
+
+        0xEA   ;D339                    ; load A into frame-count
+        0x1F   ;D33A
+        0xD3   ;D33B
+
+           ;; set v-blank? to 1
+        0x3E   ;D33C                    ; load 1 into A
+        0x01   ;D33D                    
+
+        0xEA   ;D33E                    ; load A into v-blank-prev
+        0x20   ;D33F
+        0xD3   ;D340
+
+        0x18   ;D341                    ; skip not-in-v-blank section
+        0x05   ;D342
+
+        ;; not in v-blank mode
+           ;; set b-blank? to 0
+        0x3E   ;D343                    ; load 0 into A        
+        0x00   ;D344
+
+        0xEA   ;D345                    ; load A into v-blank-prev
+        0x20   ;D346
+        0xD3   ;D347
+        
+
+        0xC3   ;D348                   ; return to beginning
+        0x1D   ;D349
+        0xD3   ;D34A
+ 
+        
+        
+        ])))
+
+
+
+
 (defn run-a-bit []
-  (-> (read-buttons)
+  (-> (read-down-button)
       (info)
       (tick)  ;; skip over data section
       (info)