Timeline for Was BCD a limiting factor on 6502 speed?
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jul 1 at 13:53 | comment | added | qwerty keyboard | 1.79Mhz.... Isn't that the same CPU clock as the NES? I heard somewhere that the BCD functionality on the 2A03 was disabled so Nintendo could skirt around patent laws. | |
| Jun 30 at 2:41 | history | became hot network question | |||
| Jun 29 at 22:31 | vote | accept | rwallace | ||
| Jun 29 at 19:47 | answer | added | Raffzahn | timeline score: 15 | |
| Jun 29 at 18:31 | comment | added | dirkt | We have a full netlist for the 6502, and it's already reverse engineered, so you can just sit down, identify the transistors used for BCD adjustment, remove them and recalculate the delay. Educated guess: It might get a tiny bit faster, but not much. | |
| Jun 29 at 17:22 | comment | added | davidbak | If there's any truth to this (and that is not to throw any shade at all on supercat believe me!) it's got to be down to a matter of gate delays in the ALU. And it that's the case then avoiding the BCD instructions would change nothing, you'd need a different ALU. | |
| Jun 29 at 16:42 | history | asked | rwallace | CC BY-SA 4.0 |