Harvey Mudd Miniature Machine
13 comments
·September 8, 2025qoez
pkasting
Went there, can definitely recommend
leopd
That was the class where I really learned how to prove things in math. Very challenging, and rewarding class.
queuebert
Francis Su is one of the GOATs
Koshkin
Nice.
Here's one from (the younger) me:
=======================
Description
=======================
24-bit words (no bytes, so no endianness)
<op> 5 <dir/ind> 1 <r1/cond> 3 <r2> 3 <val> 12
r2 = 0 means zero value
dir/ind:
0 dir
1 ind
cond:
001 eq
010 lt
1000 gt
8 regs
r0 = PC
op:
00x xx0 - type independent
01x xx0 - bitwise
10x xx0 - integer
11x xx0 - floating-point
ST 00 ; store (ignores ind/dir)
LD 02 ; load/move
BR 04 ; branch (rel/abs)
SL 20 ; shift left
SR 22 ; shift right
SA 24 ; shift right arithmetical
OR 26 ; or
AN 30 ; and
OX 32 ; or exclusive (xor)
NO 34 ; not
AD 40 ; add
SB 42 ; subtract
MU 44 ; multiply
DV 46 ; divide
CP 50 ; compare
FA 60 ; add
FS 62 ; subtract
FM 64 ; multiply
FD 66 ; divide
FC 70 ; compare
example:
LD r1, [4096] ; |03121000|
AD r1, 1 ; |40100001|
LD r2, r1 ; |02210000|
SB r2, 33 ; |42200033|
BR le, exit ; |04300001|
ST r1, [4096] ; |01201000|
exit: .
floating-point format - normalized:
<sign> 1 <exp> 7 <mantissa> 16 + 1 implicit
literals:
decimal: -8,388,608 ... 8,388,607 (can use commas)
binary (in octal): |42200033|
floating-point: 1.23e-45
character sequence 'abc' (3 characters per word)
r0 can be used as a temporary
=======================
Implementation
=======================
#include <stdio.h>
#include <ctype.h>
#define n 1024
#define trace(op) fprintf(stderr, "%04o %s\n", r0, #op)
enum {
ST = 000, /* store (ignores ind/dir) */
LD = 002, /* load/move */
BR = 004, /* branch (ignores ind/dir) */
SL = 020, /* shift left */
SR = 022, /* shift right */
SA = 024, /* shift right arithmetical */
OR = 026, /* or */
AN = 030, /* and */
OX = 032, /* or exclusive (xor) */
NO = 034, /* not */
AD = 040, /* add */
SB = 042, /* subtract */
MU = 044, /* multiply */
DV = 046, /* divide */
CP = 050, /* compare */
FA = 060, /* add */
FS = 062, /* subtract */
FM = 064, /* multiply */
FD = 066, /* divide */
FC = 070 /* compare */
};
int main() {
static int b[n];
/* load image */
int c, *p, s, z;
static int r[8];
for (s = 21, p = b; p < b + n && (c = getchar()) > 0;)
if (isdigit(c) && c <= '7') {
*p |= (~0x30 & c) << s;
if (s)
s -=3;
else
s = 21, ++p;
}
/* run image */
c = 7;
while (r[0] >= 0 && r[0] < n) {
int i, o, d, x, y, v, r0;
i = b[r0 = r[0]++]; /* inc PC */
o = (i >> 19 & 31) << 1;
d = !(i >> 18 & 1);
x = i >> 15 & 7;
y = i >> 12 & 7;
v = ((i << 20) >> 20) + (y ? r[y] : 0); /* assuming 32-bit ints */
switch(o) {
case ST: b[v] = r[x]; trace(ST); break;
case LD: r[x] = d ? v : b[v]; trace(LD); break;
case BR: if (x & c) r[0] += v; trace(BR); break;
case SL: r[x] <<= v; c = r[x] == 0 ? 1 : r[x] < 0 ? 2 : 4; trace(SL); break;
case SR: r[x] >> v; c = r[x] == 0 ? 1 : r[x] < 0 ? 2 : 4; trace(SR); break;
case SA: r[x] >> (unsigned) v; c = r[x] == 0 ? 1 : r[x] < 0 ? 2 : 4; trace(SA); break;
case OR: r[x] |= (d ? v : b[v]); c = r[x] == 0 ? 1 : r[x] < 0 ? 2 : 4; trace(OR); break;
case AN: r[x] &= (d ? v : b[v]); c = r[x] == 0 ? 1 : r[x] < 0 ? 2 : 4; trace(AN); break;
case OX: r[x] ^= (d ? v : b[v]); c = r[x] == 0 ? 1 : r[x] < 0 ? 2 : 4; trace(OX); break;
case NO: r[x] = ~r[x]; c = r[x] == 0 ? 1 : r[x] < 0 ? 2 : 4; trace(NO); break;
case AD: r[x] += (d ? v : b[v]); c = r[x] == 0 ? 1 : r[x] < 0 ? 2 : 4; trace(AD); break;
case SB: r[x] -= (d ? v : b[v]); c = r[x] == 0 ? 1 : r[x] < 0 ? 2 : 4; trace(SB); break;
case MU: r[x] *= (d ? v : b[v]); c = r[x] == 0 ? 1 : r[x] < 0 ? 2 : 4; trace(MU); break;
case DV: r[x + 1] = r[x] % (d ? v : b[v]); r[x] /= (d ? v : b[v]); c = r[x] == 0 ? 1 : r[x] < 0 ? 2 : 4; trace(DV); break;
case CP: c = r[x] == (d ? v : b[v]) ? 1 : r[x] < (d ? v : b[v]) ? 2 : 4; trace(CP); break;
case FA: trace(FA); break; /* TODO */
case FS: trace(FS); break; /* TODO */
case FM: trace(FM); break; /* TODO */
case FD: trace(FD); break; /* TODO */
case FC: trace(FC); break; /* TODO */
}
}
/* print image */
for (z = 0, p = b; p < b + n; ++p)
if (*p) {
int m;
if (z) {
puts("00000000");
if (z > 3)
puts("........");
else if (z > 1)
puts("00000000");
if (z > 2)
puts("00000000");
z = 0;
}
for (s = 21, m = 7 << s; m; m >>= 3, s -= 3)
putchar(0x30 | (*p & m) >> s);
putchar('\n');
}
else
++z;
return 0;
}
=======================
Example: Bubble Sort
=======================
0000 LD r1, 10 ; n = 8 02100010
repeat:
0001 SB r1, 1 ; n = n - 1 42100001
0002 LD r2, 0 ; i = 0 02200000
0003 LD r3, 0 ; f = false 02300000
compare:
0004 LD r4, [r2 + data] ; 03420021
0005 CP r4, [r2 + data + 1] ; 51420022
0006 BR le, next ; 04300004
0007 LD r5, [r2 + data + 1] ; swap 03520022
0010 ST r5, [r2 + data] ; 00520021
0011 ST r4, [r2 + data + 1] ; 00420022
0012 LD r3, 1 ; f = true 02300001
next:
0013 AD r2, 1 ; i = i + 1 40200001
0014 CP r2, r1 ; i < n ? 50210000
0015 BR lt, compare ; 04207766
0016 CP r3, 0 ; f = false ? 50300000
0017 BR eq, 2000 ; exit 04102000
0020 BR , repeat ; 04707760
data:
0021 9 ; 00000011
0022 8 ; 00000010
0023 5 ; 00000005
0024 6 ; 00000006
0025 3 ; 00000003
0026 7 ; 00000007
0027 2 ; 00000002
0030 1 ; 00000001unzadunza
I got all excited until I realized Harvey Mudd isn't Henry Mudd. This project would have had a lot more cred, in my book, if it were the latter.
notherhack
I was hoping for Harry Mudd's android-making machine from Star Trek OG. https://en.wikipedia.org/wiki/I%2C_Mudd
null
[deleted]
neaden
I feel like I'm missing something, Henry Mudd Harvey Mudd's son?
modeless
I'm guessing he was probably trying to refer to Harry Mudd, the Star Trek character?
ChrisMarshallNY
Harcourt Fenton Mudd.
gs17
I'd be more excited if it was by Harry Mudd.
null
[deleted]
This is only tangentially related but the best course that actually made real analysis click for me was from Harvey Mudd, seems like a solid university: https://www.youtube.com/playlist?list=PL04BA7A9EB907EDAF