Added Makefile

2 files changed, 71 insertions, 0 deletions

diff --git a/examples/hello_world.bf b/examples/hello_world.bf
new file mode 100644
index 0000000..2a5b338
--- /dev/null
+++ b/examples/hello_world.bf
@@ -0,0 +1,43 @@
+[ ; This program prints "Hello World!" and a newline to the screen, its
+  ; length is 106 active command characters. [It is not the shortest.]
+
+  ; This loop is an "initial comment loop", a simple way of adding a comment
+  ; to a BF program such that you don't have to worry about any command
+  ; characters. Any ".", ",", "+", "-", "<" and ">" characters are simply
+  ; ignored, the "[" and "]" characters just have to be balanced. This
+  ; loop and the commands it contains are ignored because the current cell
+  ; defaults to a value of 0; the 0 value causes this loop to be skipped.
+]
+++++++++                ; Set Cell #0 to 8
+[
+    >++++               ; Add 4 to Cell #1; this will always set Cell #1 to 4
+    [                   ; as the cell will be cleared by the loop
+        >++             ; Add 2 to Cell #2
+        >+++            ; Add 3 to Cell #3
+        >+++            ; Add 3 to Cell #4
+        >+              ; Add 1 to Cell #5
+        <<<<-           ; Decrement the loop counter in Cell #1
+    ]                   ; Loop until Cell #1 is zero; number of iterations is 4
+    >+                  ; Add 1 to Cell #2
+    >+                  ; Add 1 to Cell #3
+    >-                  ; Subtract 1 from Cell #4
+    >>+                 ; Add 1 to Cell #6
+    [<]                 ; Move back to the first zero cell you find; this will
+                        ; be Cell #1 which was cleared by the previous loop
+    <-                  ; Decrement the loop Counter in Cell #0
+]                       ; Loop until Cell #0 is zero; number of iterations is 8
+
+; The result of this is:
+; Cell no :   0   1   2   3   4   5   6
+; Contents:   0   0  72 104  88  32   8
+; Pointer :   ^
+
+>>.                     ; Cell #2 has value 72 which is 'H'
+>---.                   ; Subtract 3 from Cell #3 to get 101 which is 'e'
++++++++..+++.           ; Likewise for 'llo' from Cell #3
+>>.                     ; Cell #5 is 32 for the space
+<-.                     ; Subtract 1 from Cell #4 for 87 to give a 'W'
+<.                      ; Cell #3 was set to 'o' from the end of 'Hello'
++++.------.--------.    ; Cell #3 for 'rl' and 'd'
+>>+.                    ; Add 1 to Cell #5 gives us an exclamation point
+>++.                    ; And finally a newline from Cell #6
diff --git a/examples/rot13.bf b/examples/rot13.bf
new file mode 100644
index 0000000..3ce3faf
--- /dev/null
+++ b/examples/rot13.bf
@@ -0,0 +1,28 @@
+-,+[                          ; Read first character and start outer character reading loop
+    -[                        ; Skip forward if character is 0
+        >>++++[>++++++++<-]   ; Set up divisor (32) for division loop
+                              ;   (MEMORY LAYOUT: dividend copy remainder divisor quotient zero zero)
+        <+<-[                 ; Set up dividend (x minus 1) and enter division loop
+            >+>+>-[>>>]       ; Increase copy and remainder / reduce divisor / Normal case: skip forward
+            <[[>+<-]>>+>]     ; Special case: move remainder back to divisor and increase quotient
+            <<<<<-            ; Decrement dividend
+        ]                     ; End division loop
+    ]>>>[-]+                  ; End skip loop; zero former divisor and reuse space for a flag
+    >--[-[<->+++[-]]]<[       ;    Zero that flag unless quotient was 2 or 3; zero quotient; check flag
+        ++++++++++++<[        ; If flag then set up divisor (13) for second division loop
+                              ;   (MEMORY LAYOUT: zero copy dividend divisor remainder quotient zero zero)
+            >-[>+>>]          ; Reduce divisor; Normal case: increase remainder
+            >[+[<+>-]>+>>]    ; Special case: increase remainder / move it back to divisor / increase quotient
+            <<<<<-            ; Decrease dividend
+        ]                     ; End division loop
+        >>[<+>-]              ; Add remainder back to divisor to get a useful 13
+        >[                    ; Skip forward if quotient was 0
+            -[                ; Decrement quotient and skip forward if quotient was 1
+                -<<[-]>>      ; Zero quotient and divisor if quotient was 2
+            ]<<[<<->>-]>>     ; Zero divisor and subtract 13 from copy if quotient was 1
+        ]<<[<<+>>-]           ; Zero divisor and add 13 to copy if quotient was 0
+    ]                         ; End outer skip loop (jump to here if ((character minus 1)/32) was not 2 or 3)
+    <[-]                      ; Clear remainder from first division if second division was skipped
+    <.[-]                     ; Output ROT13ed character from copy and clear it
+    <-,+                      ; Read next character
+]                             ; End character reading loop