I wanted a computer, but all I got was a transistor

1. I wanted a computer, but all I got was a transistor. Denis Defreyne 1
2. 2 I will explain how to build a computer from scratch. I cannot do this without taking some shortcuts. I will tell lies. CAUTION
4. In the beginning, the transistor was created. 4
5. 5 GATE SOURCE DRAIN
6. 6 GATE SOURCE DRAIN
7. 7 GATE SOURCE DRAIN
12. 12 AND
17. OR 17
18. Now we have gates, and we can forget about transistors. 18
19. 19 OR AND XOR NAND NOT …
20. A B Sum 0 0 0 0 1 1 1 0 1 1 1 0 20
21. A B Carry 0 0 0 1 A B Sum Carry 0 0 0 0 1 1 1 0 1 1 1 0 21 AND XOR
22. 22 AND A B CARRY XOR SUM
23. ADD CARRY SUM A B 23
24. 24 ADD CARRY SUM A B CARRY
25. 25 ADD SUM 0 A 0 B 0
26. 26 ADD SUM 0 A 0 B 0 ADD SUM 1 A 1 B 1
27. 27 ADD SUM 0 A 0 B 0 ADD SUM 1 A 1 B 1 ADD SUM 0 A 0 B 0 ADD SUM 1 A 1 B 1 ADD A 2 B 2 SUM 2
28. 28 ADD A B SUM
29. ADD 00010001 00000101 00010110 29
30. ADD 17 5 22 30
31. 31 ADD R A B MUL R A B DIV R A B MOD R A B
32. A B ADD MUL DIV MOD R R R R 32
33. A B ADD MUL DIV MOD MUX S R 33
34. 34 MUX
35. 35 0 MUX
36. 36 1 MUX
37. 37 2 MUX
38. 38 3 MUX
39. 39 A B ADD MUL DIV MOD MUX S R
40. 40 ALU R A B S
41. A B S Result 15 7 0 (+) 22 15 7 1 (*) 105 15 7 2 (/) 2 15 7 3 (%) 1 41
42. Now we have an arithmetic logic unit. 42
43. 43 OR NOT OR NOT Q S R
44. OR NOT OR NOT Q S R 44
45. OR NOT OR NOT Q S R 45
46. OR NOT OR NOT Q S R 46
47. OR NOT OR NOT Q S R 47
48. OR NOT OR NOT Q S R 48
49. 49 SR-LATCH S R Q set reset
50. D-LATCH D E Q 50 data enable write
51. 51 D-LATCH D 0 Q 0 D-LATCH D 1 Q 1 D-LATCH D 2 Q 2 D-LATCH D 3 Q 3 D-LATCH D 4 Q 4 D-LATCH D 5 Q 5 D-LATCH D 6 Q 6 D-LATCH D 7 Q 7 E
52. 52 REGISTER (8 BIT) D E Q
53. Now we have registers. 53
54. Q: What distinguishes a computer from a simple calculator? 54
55. A: You can program a computer, but not a calculator. 55
56. 56 OPCODE VALUE 1 VALUE 2 2 7 15
57. 57 OPCODE VALUE 1 VALUE 2 ALU R
58. OPCODE VALUE 1 VALUE 2 ALU REGISTER (8 BIT) 1 58
59. OPCODE VALUE 1 VALUE 2 ALU REGISTER FILE OUTPUT REG 1 59
60. OPCODE INPUT REG 1 INPUT REG 2 REGISTER FILE OUTPUT REG ALU 0 0 1 60
61. 61 OPCODE INPUT REG 1 INPUT REG 2 OUTPUT REG
62. 62 INSTRUCTION REGISTER OPCODE INPUT REG 1 INPUT REG 2 OUTPUT REG
63. 63 MEMORY INSTRUCTION REGISTER OPCODE INPUT REG 1 INPUT REG 2 OUTPUT REG
64. MEMORY INSTRUCTION REGISTER OPCODE INPUT REG 1 INPUT REG 2 OUTPUT REG 0 64
65. 65 INSTRUCTION POINTER REGISTER MEMORY INSTRUCTION REGISTER OPCODE INPUT REG 1 INPUT REG 2 OUTPUT REG
66. 66 INSTRUCTION POINTER REGISTER MEMORY INSTRUCTION REGISTER ADD 4 OPCODE INPUT REG 1 INPUT REG 2 OUTPUT REG
67. Now we have the hardware for a programmable computer, and we can forget the hardware. 67
68. 68 0 3 0 2 Add register 0 and register 2, and store result in register 3: OPCODE INPUT REG 1 OUTPUT REG INPUT REG 2
69. 69 “add r3 r0 r2” Add register 0 and register 2, and store result in register 3:
70. 70 “add r3 r0 r2” 0 3 0 2 assembly language machine code assembler
71. 16 0 0 12 127 56 16 1 0 3 224 211 18 1 0 0 0 0 7 32 15 2 1 19 1 0 1 15 0 2 6 12 14 0 255 0 71
72. li r0, 819000 li r1, 254163 cmpi r1, 0 jeq @end mov r2, r1 mod r1, r0, r1 mov r0, r2 jmp @start prn r0 halt 72
73. 73 cmp mod add sub mul div xor or and shl shr not ARITHMETIC
74. 74 j je jne jg jge jl jle cmp mod add sub mul div xor or and shl shr not lw lh lb sw sh sb STACK FUNC SPECIAL call ret push pop prn halt BRANCHING ARITHMETIC mov li MEMORY REG
75. DEMO 75
76. github.com/ddfreyne/rcpu 76
78. 78 slack @denis / mail denis@soundcloud.com Denis Defreyne Ask me about Belgian beer.