Petit Computer Journal #28

Petit BrainF

Yeah, I was wondering just exactly how hard it is to implement a language that has only 8 operators involved. Not hard at all! Of course, I cheated and used graphic screens for my memory. It'll be probably a bit more complicated if I use straight memory. A bit.

The program cannot fit into one screen, but it's certainly a candidate for less than 100 lines program. It took me a couple hours because I was careless in moving the pointers.

The CYCLE subroutine is there to keep the variables within range, and the FB subroutine is there as a debugger that I use when debugging the program. So, I commented it out in the final version.

Another person, IAmAPersson (what a name!) was working on a version of the compiler as well. Check Petit Wikia for it. Maybe he posted it there by now.

I don't know the policy of this blogspot, but I know my policy and that is family friendly. I don't want to use the full name of the program. Thank you. Next time you designed a programming language, make sure you name it proper!

1. REM PBF BY HARRY HARDJONO
2. @INIT
3. ACLS:CLEAR
4. GPAGE 0:GCLS
5. GPAGE 1:GCLS
6. MS=30000
7. PTR=0
8. PC=0
9. MPC=0
10. CSR=0
11. 
    
12. GPAGE1:RESTORE @HELLO
13. @LOADP
14. READ A$
15. IF A$=="" GOTO @RUNP
16. FOR I=0 TO LEN(A$)-1
17. GPSET PC%256,PC/256,ASC(MID$(A$,I,1))
18. PC=PC+1:NEXT
19. GOTO @LOADP
20. 
    
21. @RUNP
22. PC=0:GPAGE 0
23. @LOOP
24. GPAGE 0:VAR=GSPOIT(PTR%256,PTR/256)
25. GPAGE 1:C=GSPOIT(PC%256,PC/256)
26. 'GOSUB @FB
27. IF C==62 THEN PTR=PTR+1:GOSUB @CYCLE:GOTO @LOOP2 
28. IF C==60 THEN PTR=PTR-1:GOSUB @CYCLE:GOTO @LOOP2
29. IF C==43 THEN VAR=VAR+1:GOSUB @CYCLE
30. IF C==45 THEN VAR=VAR-1:GOSUB @CYCLE
31. IF C==46 THEN LOCATE CSR%32,CSR/32:?CHR$(VAR);:CSR=CSR+1:GOTO @LOOP2
32. IF C==44 THEN GOSUB @GETCHAR 
33. IF C==91 THEN MPC=1:GOSUB @SR:GOTO @LOOP2
34. IF C==93 THEN MPC=1:GOSUB @SL:GOTO @LOOP2
35. IF C==0 GOTO @END 
36. GPAGE 0:GPSET PTR%256,PTR/256,VAR
37. @LOOP2
38. PC=PC+1:GOSUB @CYCLE
39. GOTO @LOOP
40. 
    
41. @FB
42. LOCATE 0,5:?PTR,PC,VAR
43. LOCATE 0,6:?CHR$(C)
44. WAIT 6
45. RETURN
46. 
    
47. @CYCLE
48. IF PC<0 THEN PC=PC+49152
49. IF PTR<0 THEN PTR=PTR+MS
50. IF VAR<0 THEN VAR=VAR+256
51. PC=PC%49152
52. PTR=PTR%MS
53. VAR=VAR%256
54. CSR=CSR%768
55. RETURN
56. 
    
57. @GETCHAR
58. A$=INKEY$():IF A$=="" GOTO @GETCHAR
59. VAR=ASC(A$):WAIT 30
60. RETURN
61. 
    
62. @SR
63. IF VAR!=0 THEN RETURN
64. PC=PC+1:GOSUB @CYCLE
65. GPAGE 1:C=GSPOIT(PC%256,PC/256)
66. IF C==91 THEN MPC=MPC+1
67. IF C==93 THEN MPC=MPC-1
68. IF MPC<=0 THEN RETURN
69. GOTO @SR
70. 
    
71. @SL
72. IF VAR==0 THEN RETURN
73. PC=PC+1:GOSUB @CYCLE
74. GPAGE 1:C=GSPOIT(PC%256,PC/256)
75. IF C==91 THEN MPC=MPC-1
76. IF C==93 THEN MPC=MPC+1
77. IF MPC<=0 THEN RETURN
78. GOTO @SL
79. 
    
80. @END
81. WAIT 600
82. END
83. 
    
84. @PLOP
85. DATA "-[>-[.-]<]"
86. DATA ">>++++[.->++++++[.-]<]"
87. DATA ""
88. 
    
89. @CAT
90. DATA ",[.,]"
91. DATA ""
92. 
    
93. @HELLO
94. DATA "+++++ +++++ [>+++++++"
95. DATA ">+++++ +++++ >+++ >+ <<<<-]"
96. DATA ">++.>+.+++++++ ..+++.>++.<<"
97. DATA "+++++ +++++ +++++"
98. DATA ".>.+++. ------ .----- --- .>+.>."
99. DATA ""