Timeline for Undocumented instructions in x86 CPU prior to 80386?
Current License: CC BY-SA 4.0
2 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 5, 2021 at 16:25 | comment | added | supercat | I suspect that during the design process, it wasn't clear whether it would be easier to have microcode that would treat the operand as an 8-bit value, treat the operand as a 4-bit value, or always perform the operation in a manner suitable for the value 10. Specifying the opcode has having a second-byte value of 0x0A accommodates all of those possibilities. | |
| Jun 4, 2021 at 23:46 | history | answered | peter ferrie | CC BY-SA 4.0 |