Spectrum ROM: Routine at 384A

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.

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.
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	jump_true to LAST: X
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.