Trig algorithms on HP RPN?

[Thomas Klemm]

(Yesterday 01:39 PM)MinkLib Wrote:  Can someone tell me if the trig algorithms for HP (and other RPN calculators) are all done in radians (behind the scenes).

Although the HP-35 only uses degrees for trigonometric functions, it still seems to use the \(\tan^{-1}\) values ​​in radians:

Code:

0-0716 0730  load constant 7        reg['C'] = 0x00700000000000
0-0717 1030  load constant 8        reg['C'] = 0x00780000000000
0-0720 0530  load constant 5        reg['C'] = 0x00785000000000
0-0721 0330  load constant 3        reg['C'] = 0x00785300000000
0-0722 1130  load constant 9        reg['C'] = 0x00785390000000
0-0723 1030  load constant 8        reg['C'] = 0x00785398000000
0-0724 0130  load constant 1        reg['C'] = 0x00785398100000
0-0725 0630  load constant 6        reg['C'] = 0x00785398160000
0-0726 0330  load constant 3        reg['C'] = 0x00785398163000
0-0727 0530  load constant 5        reg['C'] = 0x00785398163500

And then a bit later:

Code:

0-0617 1030  load constant 8        reg['C'] = 0x00099668666666
0-0620 0630  load constant 6        reg['C'] = 0x00099668666666
0-0621 0530  load constant 5        reg['C'] = 0x00099668656666
0-0622 0230  load constant 2        reg['C'] = 0x00099668652666
0-0623 0430  load constant 4        reg['C'] = 0x00099668652466
0-0624 1130  load constant 9        reg['C'] = 0x00099668652496

This is output from running x11-calc-35 with the -t option:

Code:

  -t,                      trace

Compare this to (using RAD):

1 ATAN

0.78539816340

0.1 ATAN

0.09966865249

From my understanding of CORDIC we might as well use angles in degrees.
Honestly, I don't know why that wasn't used instead.