Integral in solve on HP 42S?
02-26-2019, 05:30 AM
Post: #10
 Thomas Klemm Senior Member Posts: 1,768 Joined: Dec 2013
RE: Integral in solve on HP 42S?
(02-26-2019 03:30 AM)Thomas Okken Wrote:  Both have only one "indirect" register, which makes a lot of algorithms awkward to implement, always having to shuffle things around to get the right pointer into register 0 (which is the I equivalent on the 19C and 29C).

Compared to that, programming the 41C, where every register, even the stack registers, can be used for indirect addressing, is so much more pleasant, and the 42S inherited that programming model.

From Calculator Speed Benchmark using the N-Queens Problem:

HP-67
Code:
 LBL A  CLEAR REG         8 STO A  LBL 0  RCL 0 RCL A         x=y? GTO 4         1 STO+ 0         RCL 0 STO I         RCL A STO(i)  LBL 1  RCL B 1 + STO B         RCL 0 STO 9  LBL 2  1 STO- 9         RCL 9 x=0? GTO 0         RCL 0 STO I RCL(i)         RCL 9 STO I         Rv RCL(i) -         x=0? GTO 3         ABS RCL 0 RCL 9 -         x<>y? GTO 2  LBL 3  RCL 0 STO I         1 STO-(i)         RCL(i) x<>0? GTO 1         1 STO- 0         RCL 0 x<>0? GTO 3  LBL 4  RCL B         RTN

HP-41
Code:
 LBL A   CLRG          8 STO 11  LBL 00  RCL 00 RCL 11          X=Y? GTO 04          ISG 00 DEG          STO IND 00  LBL 01  ISG 10 DEG          RCL 00 STO 09  LBL 02  DSE 09 DEG          RCL 09 X=0? GTO 00          RCL IND 00 RCL IND 09 -          X=0? GTO 03          ABS RCL 00 RCL 09 -          X<>Y? GTO 02  LBL 03  DSE IND 00 GTO 01          DSE 00 GTO 03  LBL 04  RCL 10          RTN

Compare e.g. the inner loop between LBL 2GTO 2:

HP-67
Code:
        RCL 0 STO I RCL(i)         RCL 9 STO I         Rv RCL(i) -

HP-41
Code:
         RCL IND 00 RCL IND 09 -

Cheers
Thomas
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 Messages In This Thread Integral in solve on HP 42S? - lrdheat - 02-24-2019, 06:29 PM RE: Integral in solve on HP 42S? - Thomas Klemm - 02-24-2019, 08:13 PM RE: Integral in solve on HP 42S? - Gerald H - 02-25-2019, 05:17 AM RE: Integral in solve on HP 42S? - Werner - 02-25-2019, 07:43 AM RE: Integral in solve on HP 42S? - lrdheat - 02-24-2019, 08:15 PM RE: Integral in solve on HP 42S? - Thomas Klemm - 02-25-2019, 07:47 AM RE: Integral in solve on HP 42S? - Thomas Klemm - 02-25-2019, 08:09 AM RE: Integral in solve on HP 42S? - Werner - 02-26-2019, 07:41 AM RE: Integral in solve on HP 42S? - ijabbott - 02-26-2019, 08:39 AM RE: Integral in solve on HP 42S? - lrdheat - 02-26-2019, 03:15 AM RE: Integral in solve on HP 42S? - Thomas Okken - 02-26-2019, 03:30 AM RE: Integral in solve on HP 42S? - Thomas Klemm - 02-26-2019 05:30 AM RE: Integral in solve on HP 42S? - Gerald H - 02-26-2019, 09:29 AM

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