Previous File Previous Page Single Page Next Page Next File

* NAME BASIC-MTHPAK DOC. 70181832000 REV. A PAGE 25

0839 * 0840 * 0841 * SINGLE PRECISION MULTIPLIPLICATION 0842 * 0843 * CALLING SEQUENCE: 0844 * 0845 * JST M$11 MULTIPLICAND IN THE A REGISTER 0846 * DAC ARG2 POINTER TO MULTIPLIER 0847 * ......RETURN PRODUCT TRANSPOSED SO THAT LEAST SIGNIFI- 0848 * CANT PART IS IN A REGISTER 0849 * 0850 * 0851 * THE ROUTINE EXPECTS THE MULTIPLICAND AND MULTIPLIER TO BE IN 0852 * SINGLE PRECISION FIXED POINT FORMAT WITH POSITIVEL SIGNS. THE LEAST 0853 * SIGNIFICANT BIT OF THE MULTIPLIER IS TESTED. IF IT IS ONE, THE 0854 * MULTIPLICAND IS ADDED TO THE PRODUCT WHICH IS INITIALLY ZERO. THE 0855 * MULTIPLIRR AND THE PRODUCT ARE SHIFTED RIGHT, AND THE NEXT LEAST 0856 * SIGNIFICANT BIT OF THE MULTIPLIER IS TESTED. THE PROCESS IS 0857 * REPEATED FOR THE 15 MAGNITUDE BITS OF THE MULTLPLIER. THE RESULT 0858 * IS THEN SHIFTED SO THAT IT IS DOUBLE PRECISION FIXED POINT FORMAT. 0859 * THE ANSWER IS TRANSPOSED SO THAT THE LEAST SIGNIFICANT PART IS IN 0860 * THE A REGISTER, AND THE ROUTINE EXITS. 0861 * 0862 * 0863 00507 0 000000 M$11 DAC ** INTEGER MULTIPLY ENTRY 0864 00510 0 04 00200 STA HIGH SAVE THE MULTIPLICAND 0865 * 0866 * INITIALIZE THE LOOP COUNTER AND POSITION THE MULTIPLIER 0867 * 0868 00511 0 02 00527 LDA M17 INITIALIZE LOOP COUNTER TO THE NUMBER OF 0869 * MAGNITUDE BITS IN MULTIPLIER 0870 00512 0 04 00272 STA CNTR 0871 00513 0 02 00507 LDA M$11 LOAD MULTIPLIER 0872 00514 0 10 00070 JST LARG LOAD ARGUMENT ROUTINE 0873 00515 0400 57 LRL 17 CLEAR A, SHIFT LSB OF MULTIPLIER INTO C BIT 0874 * 0875 * MULTIPLY LOOP 0876 * 0877 00516 100001 M101 SRC TEST LSB 0878 00517 0 06 00200 ADD HIGH LSB IS ONE-ADD THE MULTIPLICAND TO THE PRO- 0879 * DUCT 0880 00520 0400 77 LRL 1 SHIFT LSB OF MULTIPLIER INTO C BIT 0881 00521 0 12 00272 IRS CNTR BUMP COUNTER 0882 00522 0 01 00516 JMP M101 LOOP TO TEST LSB OF MULTIPLIER IF COUNTER 0883 * IS NON-ZERO 0884 * 0885 * FORMAT THE RESULT 0886 * 0887 00523 0414 77 LGL 1 IF THE COUNTER IS ZERO, PUT THW RESULT IN 0888 00524 0400 77 LRL 1 DOUBLE PRECISION FORMAT BY CLEARING BIT ONE
Previous File Previous Page Single Page Next Page Next File