Based on https://laughtonelectronics.com/Arcana/One-bit%20computer/One-bit%20computer.html
I'm trying to convert this to markdown, in the meantime the formatting is badly broken, sorry.
- Every 32 bit instruction is single cycle.
- it can do like a lot of MIPS.
- Tips out at over 4MHz, thats faster than a 6502!
- 7 one bit user inputs
- 7 one bit user outputs
- System halted output.
- 52 powerfully psychedelic instructions
- Simple hardware architecture using high-availability components.
- A flag register.
- None of those bothersome interrupt things.
- Programmable with up to 256 instructions.
- Completely stack overflow protected, by not having a stack.
To compile the assembler: gcc *.c -o 1bit-as
To assemble with it: 1bit-as test1.asm
(output is in output.bin)
To burn with minipro to a 28C64 eeprom:
(minipro -p AT28C64 -s -w output.bin)
To compile the uploader: gcc *.c -o 1bit-dude
To upload with it: 1bit-dude -p /dev/ttyUSB0 -f output.bin
- Use uppercase
- Don't put instructions on lines with labels
- There are no actual commas, SETBJMP 4 JUMPDEST
- See examples and test programs.
- The reset vector is 0x00.
On the basic hardware, you will need to use a pre-programmed memory chip. If you are using the version with the serial upload option, the uploader software can write your binary to a SRAM or 28Cxx Series of eeprom in the system. (no special firmware is required on the 1-bit) (1bit-dude -p /dev/ttyUSB28 -f wooble.bin)
There are a few flavours of the hardware.
Basic system:
System with serial upload:
So what can a 1 bit computer be used for?
- It can be used as a simple PLC
- Serial is 1 bit, so it can do that...
Questions?
twitter @ruenahcmohr
ThisIsALabel:
; This is a comment
NAME EQU VALUE
where value is either a number, or the name of something previously defined. (SINGLE EQU ONE)
example: PI EQU 3
no equations or math or junk, just values.
NAME EQU
delete value 'name'
** By reading this you are responsible for any mental damage
caused by trying to understand this instruction set. **
This machine only actually has one micro instruction.
Effectivly, for the purposes of programming the following occurs:
-
The output is written
-
An input is read to the F register
-
An address is jumped to (which one depending on the F register)
Machine Instruction:
if F false: [ I, O ] [ jump ]
if F true: [ I, O ] [ jump ]
Order of operations:
- (latch outputs, read inputs), jump
- The value output depends on the status of the F register from the previous instruction.
- The value of the F register after the read determines the jump performed.
Where:
a 8 bit address
i 3 bit input address
o 3 bit output address
v 1 bit value
-- machine set
NOP
HALT
-- mostly I/O set
SETB o
SETBJMP o, a
SETBSKIP o
CSETB o, o
CSBFS o
CSBFC o
CLRB o
CLRBJMP o, a
CLRBSKIP o
CCLRB o, o
CCBFS o
CCBFC o
OUTIN o, i
OUTINJMP o, i, a
OUTV o, v
OUTVJMP o, v, a
OUT o
OUTI o
OUTIJMP o, a
OUTJMP o, a
COUTF o, v, o, v
COUTFS o, v
COUTFC o, v
IN i
INJMP i, a
INJPS i, a
INJPC i, a
CINF i, i
-- mostly flow control set
JMP a
JPS a
JPC a
JMPT a
JPV v, a
JPNV v, a
JPIV i, v, a
JPINV i, v, a
FORKF af, at
FORKI i, af, at
WAITIS i
WAITISJMP i, a
WAITIC i
WAITICJMP i, a
SKIPIC i
SKIPIS i
SKIPFC
SKIPFS
REPTIC i
REPTIS i
REPTFC
REPTFS
-- math / ALU instructions
Flag modified / output modified.
| F | Output | Cycles | |
|---|---|---|---|
| REPTFC | 1 | ||
| REPTFS | 1 | ||
| SKIPFC | 1 | ||
| SKIPFS | 1 | ||
| FORKF | 1 | ||
| NOP | 1 | ||
| HALT | inf | ||
| JMP | 1 | ||
| JMPT | 1 | ||
| JPS | 1 | ||
| JPC | 1 | ||
| JPV | 1 | ||
| JPNV | 1 | ||
| SETB | Y | 1 | |
| SETBJMP | Y | 1 | |
| SETBSKIP | Y | 1 | |
| CSETB | Y | 1 | |
| CSBFS | M | 1 | |
| CSBFC | M | 1 | |
| CLRB | Y | 1 | |
| CLRBJMP | Y | 1 | |
| CLRBSKIP | Y | 1 | |
| CCLRB | Y | 1 | |
| CCBFS | M | 1 | |
| CCBFC | M | 1 | |
| OUTV | Y | 1 | |
| COUTVFS | M | 1 | |
| COUTVFc | M | 1 | |
| OUTVJMP | Y | 1 | |
| OUT | Y | 1 | |
| OUTI | Y | 1 | |
| OUTIJMP | Y | 1 | |
| OUTJMP | Y | 1 | |
| COUTF | Y | 1 | |
| IN | Y | 1 | |
| INJMP | Y | 1 | |
| INJPS | Y | 1 | |
| INJPC | Y | 1 | |
| CINF | Y | 1 | |
| JPIV | Y | 1 | |
| JPINV | Y | 1 | |
| FORKI | Y | 1 | |
| WAITIS | Y | - | |
| WAITISJMP | Y | - | |
| WAITIC | Y | - | |
| WAITICJMP | Y | - | |
| SKIPIC | Y | 1 | |
| SKIPIS | Y | 1 | |
| REPTIC | Y | 1 | |
| REPTIS | Y | 1 | |
| OUTIN | Y | Y | 1 |
| OUTINJMP | Y | Y | 1 |
M = maybe (conditional)
===================================================================
The format of these instruction details is as follows:
Instruction_name
if F false: Bit read to F register, Output operation performed*, address jumped to
if F true: Bit read to F register, Output operation performed*, address jumped to
detailed description of instruction.
The output operation depends on the old F value, not the new one.
F is the flag register. (data bus)
A is the 'current address'
NC is the No Connect output (used to indicate if the system has halted)
Input 7 is the loopback input. Reading this will not modify the F register.
arguments:
a: 8 bit address
i: 3 bit input
o: 3 bit output
v: 1 bit value
NOP
test 7, set NC, jump A+1
test 7, set NC, jump A+1
No operation, machine is idle for 1 cycle.
1 is written to the NC output
HALT
test 7, clear NC, jump A
test 7, clear NC, jump A
Halt machine.
Reset is the only escape
0 is written to the NC output (machine halts by looping this instruction)
SETB o
test 7, set o, jump A+1
test 7, set o, jump A+1
(set bit)
Set output bit o
SETBSKIP o
test 7, set o, jump A+2
test 7, set o, jump A+2
(set bit, skip)
Set output bit o, skip next instruction
CSBFS o
test 7, set NC , jump A+1
test 7, set o, jump A+1
(conditional set bit if F set)
Set output bit o if F is set (else NOP)
CSBFC o
test 7, set o , jump A+1
test 7, set NC, jump A+1
(conditional set bit if F clear)
Set output bit o if F is clear (else NOP)
SETBJMP o, a
test 7, set o, jump a
test 7, set o, jump a
(set bit, jump)
Set output bit o. Jump to a
CSETB of, ot
test 7, set of, jump A+1
test 7, set ot, jump A+1
(conditional set bit)
If F is clear, set bit Of
If F is set, set bit Ot
CLRB o
test 7, clear o, jump A+1
test 7, clear o, jump A+1
(clear bit)
Clear output bit o
CLRBSKIP o
test 7, clear o, jump A+2
test 7, clear o, jump A+2
(clear bit, skip)
Clear output bit o, skip next instruction
CCBFS o
test 7, set NC , jump A+1
test 7, clear o, jump A+1
(conditional clear bit if F set)
Clear output bit o if F is set (else NOP)
CCBFC o
test 7, clear o , jump A+1
test 7, set NC, jump A+1
(conditional clear bit if F clear)
Clear output bit o if F is clear (else NOP)
CLRBJMP o, a
test 7, clear o, jump a
test 7, clear o, jump a
(clear bit, jump)
Clear output bit o and jump to a
CCLRB of, ot
test 7, clear of, jump A+1
test 7, clear ot, jump A+1
(conditional clear bit)
If F is clear, clear bit Of
If F is set, clear bit Ot
OUTIN o, i
test i, set o, jump A+1
test i, clear o, jump A+1
(output, input)
write the value of the F register to output o
read the value of i to the F register
OUTINJMP o, i, a
test i, set o, jump a
test i, clear o, jump a
(output, input, and jump)
write the value of the F register to output o
read the value of i to the F register
jump to a
OUTV o, v
test 7, write v to o, jump A+1
test 7, write v to o, jump A+1
(output value)
write the value v to output o
COUTVFS o, v
test 7, set NC, jump A+1
test 7, write v to o, jump A+1
(conditional output value if F is set)
write the value v to output o if F is set (else NOP)
COUTVFC o, v
test 7, write v to o, jump A+1
test 7, set NC, jump A+1
(conditional output value if F is clear)
write the value v to output o if F is clear (else NOP)
OUTVJMP o, v, a
test 7, write v to o, jump a
test 7, write v to o, jump a
(output value and jump)
write the value v to output o, jump to a
OUT o
test 7, set o, jump A+1
test 7, clear o, jump A+1
write the value of the F register to output o
OUTI o
test 7, clear o, jump A+1
test 7, set o, jump A+1
(output inverse)
write the inverse value of the F register to output o
OUTJMP o, a
test 7, set o, jump a
test 7, clear o, jump a
(output and jump)
write the value of the F register to output o, and jump to address a
OUTIJMP o, a
test 7, clear o, jump a
test 7, set o, jump a
(output inverse and jump)
write the inverse value of the F register to output o, and jump to address a
COUTF of, vf, ot, vt
test 7, set/clear of, jump A+1
test 7, set/clear ot, jump A+1
(conditionally output F)
write vf to of if F is clear
write vt to ot if F is set
IN i
test i, set NC, jump A+1
test i, set NC, jump A+1
load the value of i into the F register
INJMP i, a
test i, set NC, jump a
test i, set NC, jump a
(input and jump)
load the value of i into the F register and jump to address
INJPS i, a
test i, set NC, jump A+1
test i, set NC, jump a
(jump if input i is set)
load the value of i into the F register and jump to address a if it is set
INJPC i, a
test i, set NC, jump a
test i, set NC, jump A+1
(jump if input i is clear)
load the value of i into the F register and jump to address a if it is clear
CINF if, it
test if, set NC, jump A+1
test it, set NC, jump A+1
(conditional input)
load the value of 'if' into the F register if the F register is clear;
else
load the value of 'it' into the F register.
JMP a
test 7, set NC, jump a
test 7, set NC, jump a
Jump to a
1 is written to the NC output
JMPT a
test 7, set NC, jump a
test 7, set NC, jump a+1
(Table Jump)
Jump to a+F. If F is 1, the jump will be to the specificed address + 1
1 is written to the NC output
JPS a
test 7, set NC, jump A+1
test 7, set NC, jump a
(jump set)
Jump to a if F is set
1 is written to the NC output
JPC a
test 7, set NC, jump a
test 7, set NC, jump A+1
(jump clear)
Jump to a if F is clear
1 is written to the NC output
JPV v, a
test 7, set NC, if(v = 1) jump A+1 else jump a
test 7, set NC, if(v = 1) jump a else jump A+1
(jump if value)
Jump to a if F is the value v
1 is written to the NC output
JPNV v, a
test 7, set NC, if(v = 1) jump a else jump A+1
test 7, set NC, if(v = 1) jump A+1 else jump a
(jump if not value)
Jump to a if F is not the value v
1 is written to the NC output
JPIV i, v, a
test i, set NC, if(v = 1) jump A+1 else jump a
test i, set NC, if(v = 1) jump a else jump A+1
(jump if input value)
Jump to a if i is the value v
1 is written to the NC output
JPINV i, v, a
test i, set NC, if(v = 1) jump a else jump A+1
test i, set NC, if(v = 1) jump A+1 else jump a
(jump if input not value)
Jump to a if i is not the value v
1 is written to the NC output
FORKF af, at
test 7, set NC, jump af
test 7, set NC, jump at
(fork F)
If F is clear, jump to af.
If F is set, jump to at.
1 is written to the NC output
'Its a fork Jim, but not as we know it.`
FORKI i, af, at
test i, set NC, jump af
test i, set NC, jump at
(fork with input)
copy value of i to F
If F is clear, jump to af.
If F is set, jump to at.
1 is written to the NC output
WAITIS i
test i, set NC, jump A
test i, set NC, jump A+1
(wait input set)
copy value of i to F
Poll i untill it is set.
1 is written to the NC output
WAITISJMP i, a
test i, set NC, jump A
test i, set NC, jump a
(wait input set, jump)
copy value of i to F
Poll i untill it is set.
1 is written to the NC output
WAITIC i
test i, set NC, jump A+1
test i, set NC, jump A
(wait input clear)
copy value of i to F
Poll i untill it is clear.
1 is written to the NC output
WAITICJMP i, a
test i, set NC, jump a
test i, set NC, jump A
(wait input clear, jump)
copy value of i to F
Poll i untill it is clear.
1 is written to the NC output
SKIPIC i
test i, set NC, jump A+2
test i, set NC, jump A+1
(skip input clear)
copy value of i to F
Skip the next instruction if i is clear
1 is written to the NC output
SKIPIS i
test i, set NC, jump A+1
test i, set NC, jump A+2
(skip input set)
copy value of i to F
Skip the next instruction if i is set
1 is written to the NC output
SKIPFC
test 7, set NC, jump A+2
test 7, set NC, jump A+1
(skip F clear)
Skip the next instruction if i is clear
1 is written to the NC output
SKIPFS
test 7, set NC, jump A+1
test 7, set NC, jump A+2
(skip F set)
Skip the next instruction if i is set
1 is written to the NC output
REPTIC i
test i, set NC, jump A-1
test i, set NC, jump A+1
(repeat while input clear)
copy value of i to F
Repeat the last instruction if i is clear
1 is written to the NC output
REPTIS i
test i, set NC, jump A+1
test i, set NC, jump A-1
(repeat while input set)
copy value of i to F
Repeat the last instruction if i is set
1 is written to the NC output
REPTFC
test 7, set NC, jump A-1
test 7, set NC, jump A+1
(repeat F clear)
Repeat the last instruction if F is clear
1 is written to the NC output
REPTFS
test 7, set NC, jump A+1
test 7, set NC, jump A-1
(repeat F set)
Repeat the last instruction if F is set
1 is written to the NC output
==========================================================================
Why do these always have an ascii table?
00 000 [NUL] 20 032 [ ] 40 064 [@ ] 60 096 [` ]
01 001 [SOH] 21 033 [! ] 41 065 [A ] 61 097 [a ]
02 002 [STX] 22 034 [" ] 42 066 [B ] 62 098 [b ]
03 003 [ETX] 23 035 [# ] 43 067 [C ] 63 099 [c ]
04 004 [EOT] 24 036 [$ ] 44 068 [D ] 64 100 [d ]
05 005 [ENQ] 25 037 [% ] 45 069 [E ] 65 101 [e ]
06 006 [ACK] 26 038 [& ] 46 070 [F ] 66 102 [f ]
07 007 [BEL] 27 039 [' ] 47 071 [G ] 67 103 [g ]
08 008 [BS ] 28 040 [( ] 48 072 [H ] 68 104 [h ]
09 009 [HT ] 29 041 [) ] 49 073 [I ] 69 105 [i ]
0A 010 [LF ] 2A 042 [* ] 4A 074 [J ] 6A 106 [j ]
0B 011 [VT ] 2B 043 [+ ] 4B 075 [K ] 6B 107 [k ]
0C 012 [FF ] 2C 044 [, ] 4C 076 [L ] 6C 108 [l ]
0D 013 [CR ] 2D 045 [- ] 4D 077 [M ] 6D 109 [m ]
0E 014 [SO ] 2E 046 [. ] 4E 078 [N ] 6E 110 [n ]
0F 015 [SI ] 2F 047 [/ ] 4F 079 [O ] 6F 111 [o ]
10 016 [DLE] 30 048 [0 ] 50 080 [P ] 70 112 [p ]
11 017 [DC1] 31 049 [1 ] 51 081 [Q ] 71 113 [q ]
12 018 [DC2] 32 050 [2 ] 52 082 [R ] 72 114 [r ]
13 019 [DC3] 33 051 [3 ] 53 083 [S ] 73 115 [s ]
14 020 [DC4] 34 052 [4 ] 54 084 [T ] 74 116 [t ]
15 021 [NAK] 35 053 [5 ] 55 085 [U ] 75 117 [u ]
16 022 [SYN] 36 054 [6 ] 56 086 [V ] 76 118 [v ]
17 023 [ETB] 37 055 [7 ] 57 087 [W ] 77 119 [w ]
18 024 [CAN] 38 056 [8 ] 58 088 [X ] 78 120 [x ]
19 025 [EM ] 39 057 [9 ] 59 089 [Y ] 79 121 [y ]
1A 026 [SUB] 3A 058 [: ] 5A 090 [Z ] 7A 122 [z ]
1B 027 [ESC] 3B 059 [; ] 5B 091 [[ ] 7B 123 [{ ]
1C 028 [FS ] 3C 060 [< ] 5C 092 [\ ] 7C 124 [| ]
1D 029 [GS ] 3D 061 [= ] 5D 093 [] ] 7D 125 [} ]
1E 030 [RS ] 3E 062 [> ] 5E 094 [^ ] 7E 126 [~ ]
1F 031 [US ] 3F 063 [? ] 5F 095 [_ ] 7F 127 [DLE]
Why do these always have a hard to understand hex to decimal table?
| 0 1 2 3 4 5 6 7 8 9 A B C D E F
--|-----------------------------------------------------------------------------
0 | 0 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240
1 | 1 17 33 49 65 81 97 113 129 145 161 177 193 209 225 241
2 | 2 18 34 50 66 82 98 114 130 146 162 178 194 210 226 242
3 | 3 19 35 51 67 83 99 115 131 147 163 179 195 211 227 243
4 | 4 20 36 52 68 84 100 116 132 148 164 180 196 212 228 244
5 | 5 21 37 53 69 85 101 117 133 149 165 181 197 213 229 245
6 | 6 22 38 54 70 86 102 118 134 150 166 182 198 214 230 246
7 | 7 23 39 55 71 87 103 119 135 151 167 183 199 215 231 247
8 | 8 24 40 56 72 88 104 120 136 152 168 184 200 216 232 248
9 | 9 25 41 57 73 89 105 121 137 153 169 185 201 217 233 249
A | 10 26 42 58 74 90 106 122 138 154 170 186 202 218 234 250
B | 11 27 43 59 75 91 107 123 139 155 171 187 203 219 235 251
C | 12 28 44 60 76 92 108 124 140 156 172 188 204 220 236 252
D | 13 29 45 61 77 93 109 125 141 157 173 189 205 221 237 253
E | 14 30 46 62 78 94 110 126 142 158 174 190 206 222 238 254
F | 15 31 47 63 79 95 111 127 143 159 175 191 207 223 239 255
A binary to decimal chart seems to be suitable for a 1 bit computer...
0 0
1 1