File SQRT.SB (8k SABR macro assembler source file)

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/SQUARE ROOT SUBROUTINE                          OS8 FORTRAN II LIBRARY LIBRARY
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/COPYRIGHT  (C)  1974 BY DIGITAL EQUIPMENT CORPORATION
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/THE INFORMATION IN THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE
/AND SHOULD NOT BE CONSTRUED AS A COMMITMENT BY DIGITAL EQUIPMENT
/CORPORATION.  DIGITAL EQUIPMENT CORPORATION ASSUMES NO RESPONSIBILITY
/FOR ANY ERRORS THAT MAY APPEAR IN THIS MANUAL.
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/THE SOFTWARE DESCRIBED IN THIS DOCUMENT IS FURNISHED TO THE PURCHASER
/UNDER A LICENSE FOR USE ON A SINGLE COMPUTER SYSTEM AND CAN BE COPIED
/(WITH INCLUSION OF DIGITAL'S COPYRIGHT NOTICE) ONLY FOR USE IN SUCH
/SYSTEM, EXCEPT AS MAY OTHERWISE BE PROVIDED IN WRITING BY DIGITAL.
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/DIGITAL EQUIPMENT CORPORATION ASSUMES NO RESPONSIBILITY FOR THE USE
/OR RELIABILITY OF ITS SOFTWARE ON EQUIPMENT THAT IS NOT SUPPLIED BY
/DIGITAL.
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/ VERSION SQRT.03 / VERSION NUMBER IS AVAILABLE AT ENTRY POINTS ENTRY SQRT / / SQUARE ROOT ROUTINE / IF X0 IS AN APPROXIMATION FOR Y**(1/2) / THEN (X0+(Y/X0))/2 IS A BETTER APPROXIMATION / X0, BLOCK 3 Y, BLOCK 3 CNT, BLOCK 1 / / CPAGE 4 SQER, 6321 /"SQRT" ERROR FROM LOC XXXXX 2224 SQRT, 3 BLOCK 1 /ENTRY POINT TAD I SQRT DCA IN INC SQRT# TAD I SQRT DCA IN# ISZ SQRT# CALL 1,FAD IN, ARG 0 CALL 1,STO /Y=ARGUMENT ARG Y CALL 1,FAD ARG Y TAD ACH /IF Y NEGATIVE THEN ERROR SMA JMP POS CALL 1,ERROR ARG SQER CLA CLL CMA RAR AND ACH POS, SZA /IF Y=0 THEN ROOT=0 JMP NONZ RETRN SQRT NONZ, RAR CLL /FORM INITIAL APPROXIMATION TAD (1004 DCA ACH TAD ACM RAR DCA ACM TAD ACL RAR DCA ACL TAD ACH AND (4 SNA CLA TAD (2 TAD ACH DCA ACH TAD (-3 /DO 3 ITERATIONS DCA CNT INIT, CALL 1,STO ARG X0 CALL 1,FAD ARG Y CALL 1,FDV /Y/X0 ARG X0 CALL 1,FAD /(Y/X0)+X0 ARG X0 TAD ACH /((Y/X0)+X0)/2 TAD (7770 DCA ACH ISZ CNT JMP INIT RETRN SQRT END



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