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361F: THE 'STR$' FUNCTION (offset +2E)
The address of this routine is found in the table of addresses. It is called indirectly via fp_calc_2.
This subroutine handles the function STR$ X and returns a 'last value' which is a set of parameters that define a string containing what would appear on the screen if X were displayed by a PRINT command.
Input
Output
str 361F LD BC,$0001 One space is made in the work space and its address is copied to K-CUR, the address of the cursor.
3622 RST $30
3623 LD ($5C5B),HL
3626 PUSH HL This address is saved on the stack too.
3627 LD HL,($5C51) The current channel address (CURCHL) is saved on the machine stack.
362A PUSH HL
362B LD A,$FF Channel 'R' is opened, allowing the string to be 'printed' out into the work space.
362D CALL CHAN_OPEN
3630 CALL PRINT_FP The 'last value', X, is now printed out in the work space and the work space is expanded with each character.
3633 POP HL Restore CURCHL to HL and restore the flags that are appropriate to it.
3634 CALL CHAN_FLAG
3637 POP DE Restore the start address of the string.
3638 LD HL,($5C5B) Now the cursor address is one past the end of the string and hence the difference is the length.
363B AND A
363C SBC HL,DE
363E LD B,H Transfer the length to BC.
363F LD C,L
3640 CALL STK_STO Pass the parameters of the new string to the calculator stack.
3643 EX DE,HL Reset the pointers.
3644 RET Finished.
Note: see PRINT_FP for an explanation of the 'PRINT "A"+STR$ 0.1' error.
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