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384A: THE 'SQUARE ROOT' FUNCTION (offset +28)
The address of this routine is found in the table of addresses. It is called via the calculator literal +28 by the routines at CD_PRMS1 and asn. It is also called indirectly via fp_calc_2.
This subroutine handles the function SQR X and returns the positive square root of the real number X if X is positive, and zero if X is zero. A negative value of X gives rise to report A - invalid argument (via to_power).
This subroutine treats the square root operation as being X**0.5 and therefore stacks the value 0.5 and proceeds directly into to_power.
Input
Output
sqr 384A RST $28 X
384B DEFB $31 duplicate: X, X
384C DEFB $30 f_not: X, (1/0)
384D DEFB $00 jump_true to LAST: X
384E DEFB $1E
The jump is made if X=0; otherwise continue with:
384F DEFB $A2 stk_half: X, 0.5
3850 DEFB $38 end_calc
Continue into to_power to find the result of X**0.5.
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