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Yes, some links on why BCD: http://wiki.osdev.org/RTC http://wiki.osdev.org/RTC http://wiki.osdev.org/CMOS#Format_of_Bytes http://wiki.osdev.org/CMOS#Format_o
by sounds 14y ago
Yes, some links on why BCD:
http://wiki.osdev.org/RTC http://wiki.osdev.org/RTC
http://wiki.osdev.org/CMOS#Format_of_Bytes http://wiki.osdev.org/CMOS#Format_of_Bytes
- mikeash 14y agoThanks for the links. And, holy crap is PC hardware bizarre.
- Someone 14y agoBCD isn't _that_ bizarre. Many architectures had and have instructions for BCD arithmetic: x86: http://en.wikipedia.org/wiki/Intel_BCD_opcode http://en.wikipedia.org/wiki/Intel_BCD_opcode 68k: http://meseec.ce.rit.edu/eecc250-winter99/250-1-20-2000.pdf http://meseec.ce.rit.edu/eecc250-winter99/250-1-20-2000.pdf 6502: http://www.6502.org/users/dieter/bcd/bcd_0.htm http://www.6502.org/users/dieter/bcd/bcd_0.htm 6800: http://fundamentals-digital-electronics.blogspot.com/2010/09/motorola-6800-eight-bit-microprocessor.html http://fundamentals-digital-electronics.blogspot.com/2010/09... Several others, such as Power6 and Sparc64: http://speleotrove.com/decimal/ http://speleotrove.com/decimal/ (also shows this is is both still useful today)