8 ms·

It's really interesting to see that it could be done like that, but, that pseudo code you've given me would translate to a heck of a lot of MCS-48 instructions!

It's really interesting to see that it could be done like that, but, that pseudo code you've given me would translate to a heck of a lot of MCS-48 instructions! 16-bit subtraction in particular is really expensive. Potentially not much gain there?

beeforpork 6y ago
But you do have CPL -- that does not help? Anyway, without subtraction, you could do the very same with one additional add: int16_t celsius2fahrenheit(int16_t c) { int16_t f = 0; f += c << 1; f += c << 2; f += c << 3; f += c >> 2; f += c >> 3; f += c >> 5; f += 320 * 8; f >>= 3; return f; }
beeforpork 6y ago
This is the same code in MCS48 assembly. Or so I hope. ; INPUT: r1:r0 celsius * 10 ; OUTPUT: r3:r2 fahrenheit * 10 MOV A, r0 ADD A, r0 MOV r2, A MOV r4, A MOV A, r1 RLC A MOV r3, A MOV r5, A MOV A, r4 ADD A, r4 XCH A, r5 RLC A MOV r4, A MOV A, r2 ADD A, r5 XCH A, r3 ADDC A, r4 MOV r2, A MOV A, r5 ADD A, r5 XCH A, r4 RLC A MOV r5, A MOV A, r3 ADD A, r4 XCH A, r2 ADDC A, r5 MOV r3, A MOV A, r1 ADD A, r1 MOV A, r1 RRC A MOV r5, A MOV A, r0 RRC A MOV r4, A MOV A, r5 ADD A, r5 MOV A, r5 RRC A XCH A, r4 RRC A MOV r5, A MOV A, r2 ADD A, r5 XCH A, r3 ADDC A, r4 MOV r2, A MOV A, r4 ADD A, r4 MOV A, r4 RRC A XCH A, r5 RRC A MOV r4, A MOV A, r3 ADD A, r4 XCH A, r2 ADDC A, r5 MOV r3, A MOV A, r5 ADD A, r5 MOV A, r5 RRC A XCH A, r4 RRC A MOV r5, A MOV A, r4 ADD A, r4 MOV A, r4 RRC A XCH A, r5 RRC A MOV r4, A MOV A, r2 ADD A, r4 XCH A, r3 ADDC A, r5 ADD A, 10 MOV r2, A ADD A, r2 MOV A, r2 RRC A XCH A, r3 RRC A MOV r2, A MOV A, r3 ADD A, r3 MOV A, r3 RRC A XCH A, r2 RRC A MOV r3, A MOV A, r2 ADD A, r2 MOV A, r2 RRC A XCH A, r3 RRC A MOV r2, A

beeforpork 6y ago

But you do have CPL -- that does not help? Anyway, without subtraction, you could do the very same with one additional add: int16_t celsius2fahrenheit(int16_t c) { int16_t f = 0; f += c << 1; f += c << 2; f += c << 3; f += c >> 2; f += c >> 3; f += c >> 5; f += 320 * 8; f >>= 3; return f; }

beeforpork 6y ago

This is the same code in MCS48 assembly. Or so I hope. ; INPUT: r1:r0 celsius * 10 ; OUTPUT: r3:r2 fahrenheit * 10 MOV A, r0 ADD A, r0 MOV r2, A MOV r4, A MOV A, r1 RLC A MOV r3, A MOV r5, A MOV A, r4 ADD A, r4 XCH A, r5 RLC A MOV r4, A MOV A, r2 ADD A, r5 XCH A, r3 ADDC A, r4 MOV r2, A MOV A, r5 ADD A, r5 XCH A, r4 RLC A MOV r5, A MOV A, r3 ADD A, r4 XCH A, r2 ADDC A, r5 MOV r3, A MOV A, r1 ADD A, r1 MOV A, r1 RRC A MOV r5, A MOV A, r0 RRC A MOV r4, A MOV A, r5 ADD A, r5 MOV A, r5 RRC A XCH A, r4 RRC A MOV r5, A MOV A, r2 ADD A, r5 XCH A, r3 ADDC A, r4 MOV r2, A MOV A, r4 ADD A, r4 MOV A, r4 RRC A XCH A, r5 RRC A MOV r4, A MOV A, r3 ADD A, r4 XCH A, r2 ADDC A, r5 MOV r3, A MOV A, r5 ADD A, r5 MOV A, r5 RRC A XCH A, r4 RRC A MOV r5, A MOV A, r4 ADD A, r4 MOV A, r4 RRC A XCH A, r5 RRC A MOV r4, A MOV A, r2 ADD A, r4 XCH A, r3 ADDC A, r5 ADD A, 10 MOV r2, A ADD A, r2 MOV A, r2 RRC A XCH A, r3 RRC A MOV r2, A MOV A, r3 ADD A, r3 MOV A, r3 RRC A XCH A, r2 RRC A MOV r3, A MOV A, r2 ADD A, r2 MOV A, r2 RRC A XCH A, r3 RRC A MOV r2, A