Generating memory contents required to indirectly access the L-registers

If you've got the cassette adaptor the *.wav file contains the memories M10 to M14 that are generated here and the memories that are contained in the previous challenge's solution. Although the values stored in this memory dump appear different on the FX-602P the calling of the L-registers can still be performed with them.

First it is necessary to generate the character set as shown on the previous challenge's solution. Indirectly recalling a memory that contains one of the characters P, C, E, - or ' ' recalls the last 10 digits, that have been shifted by 2 places, of one of the first 5 L- registers. I expect that is as far as you can go on the FX-501P because it has only 5 levels of parenthesis. To access the less used higher numbered L- registers on FX-502P one requires the values 1P, 1C, 1E , 1- & '1 '. These are generated as shown below assuming one has the memories as generated by the previous challenge's solution.

Generation of values required to access L-registers 6 to 10 on the FX-502P (Generation does not work on the FX-602P)
Interactive Input Read out Remark
MODE, 1, 0. Go to run mode.
Min0 + MR19 = Min14 1P. o + P = 1P the address of part of the 6th L-register.
Min0 - MR18 = Min13 1C. o - -C = 1C the address of part of the 7th L-register.
Min0 - MR17 = Min12 1E. o - -E = 1E the address of part of the 8th L-register.
Min0 + MR16 = Min11 1-. o + '-' = 1- the address of part of the 9th L-register.
Min0 + MR15 = Min10 1 . o + ' ' = '1 ' the address of part of the 10th L-register.

The values in memories M10 to M19 can be used to store values indirectly in parts of the L-registers. For instance if you indirectly save a value to M10 you'll have put a value in part of the 10th L-register (i.e. memory '1 '). This memory is constant, like the M registers, and is not cleared by INV MAC. Of course if you perform a calculation which opens 10 brackets without closing any you'll over-write the value. In practice I don't think I ever used more than about 3 pending operations and so memories '-', ' ', '1P', '1C', '1-' and '1 ' were quite safe. Certainly I do not remember a single time when I lost information stored in memory '-' owing to overwriting by normal operation. Obviously these memories will become temporarily inaccessible when INV MAC is issued in Mode 1 because the numbers needed to indirectly recall them will have to be generated or reloaded. When reaccessed they will be as they were left, assuming that, in the intervening period, the calculator hasn't lost all its memories by having the batteries removed. On the FX-502P if when you recall an L-register, it contains rubbish this is a good sign that the memory hasn't been used since the batteries were put in. This a good way of discovering what the maximum number of pending opeerations that have actually been used on the calculator.