Legacy apps in Windows/OS X was Re: Old MS-DOS & Win Software

[Pete Turnbull]

On Dec 8 2005, 16:26, Jim Leonard wrote:
> Allison wrote:
> > You lived a shelterd life.
>
> I lived a young life.  I first became of programming age in late
1970s so my
> first CPUs were 6502, Z80, 68000, and 808x.

Whether it's called a Half Carry or an Auxiliary Carry seems to depend
somewhat on whose data book you read.  I've seen both used for the Z80
for example, indifferent manuals.

...in a 6800, it's called the Auxiliary Carry; in a 6809 it's called a
Half Carry.  It's bit 5 of the status register in both.

...in a Z80 and 8086 it's called the Auxiliary Carry; it's bit 4 in the
Flags register in these and 8080/8085.

...it's bit 5 in 8048 and 8051 series micrcontrollers.

There's no (visible) equivalent in a 6502 because of the way its
special Decimal Mode for BCD arithmetic works.  Ditto for a 68000.
 There isn't one in an ARM either.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York