公开(公告)号：DE2826773A1

公开(公告)日：1979-01-11

申请号：DE2826773

申请日：1978-06-19

Applicant: IBM

Inventor： LANGDON JUN GLEN GEORGE

IPC: G06F7/38 ,  G06F7/00 ,  G06F7/483 ,  G06F7/493 ,  G06F7/494 ,  G06F7/50 ,  G06F7/506

Abstract: Method and means are described for the tracking of digit significance upon operands arithmetically combined in a series of binary operations such as addition, subtraction, or shifting in a decimal computer. The digits are decimally encoded in a format having enough excess capacity such that nonsignificant digits are unique. As part of the arithmetic combining of the operand, pairs of digits of like order but possibly mismatched as to significance and by observing a predetermined rounding rule may also cause a carry value to be propagated to a digit position of higher order. In subtraction by complement addition, an additional carry is propagated to a higher order position conditioned upon there being either a local overflow, a nonsignificant subtrahend, or a nonsignificant minuend and a subtrahend less than an amount specified by a rounding rule. Between the two operands, this results in the rounding of the more precise operand to the least significant digit position of the less precise operand. The method and means are applicable to floating point, sign plus magnitude, radix and diminished radix complement number representation forms.

公开(公告)号：DE2850117A1

公开(公告)日：1979-05-23

申请号：DE2850117

申请日：1978-11-18

Applicant: IBM

Inventor： CASEY RICHARD GEORGE ,  LANGDON JUN GLEN GEORGE ,  MANTEY PATRICK EDWARD ,  WILLIAMS ROBIN

IPC: G06F3/02 ,  G06F3/033 ,  G06F3/041 ,  G06F3/048 ,  G06F3/14 ,  G09G5/08 ,  G06K15/20 ,  G06F3/00

Abstract: There is disclosed a method and means for increasing the positional accuracy of operator controlled cursors engaged in the digitized encoding of graphic information such as line drawings. The method steps comprise those of digitizing the instantaneous contact position between the cursor and the data entry surface as reference coordinates; detecting any segment of a colored object upon the surface within a predetermined area about the cursor; ascertaining the location within the area of the centroid or the like of the detected segment; and digitizing said ascertained location as a displacement from the reference coordinates. Apparatus for practicing the method comprises an independently actuable cursor formed from a position encoder and an image scanner, the scanner generating a Boolean coded array of points counterpart to a preselected surface area. The scanned array is first buffered and then used to actuate an operator viewable LED display of the scanned array on one hand and said array is sent to a CPU on the other hand. In turn, the CPU calculates the coordinates of the centroid of that array area of contiguous points having the same designated Boolean (color) 0 or 1 value. Signals representing the calculated coordinates generated by the CPU then cause the LED display to differentially indicate the calculated centroid location to the operator such as by way of a flashing display element.

公开(公告)号：DE2536586A1

公开(公告)日：1976-03-18

申请号：DE2536586

申请日：1975-08-16

Applicant: IBM

Inventor： GIANNUZZI ROBERT JOSEPH ,  LANGDON JUN GLEN GEORGE ,  PASTERNAK EDWARD

IPC: G06F3/023 ,  G06F3/147 ,  G06F15/02 ,  H01H13/84 ,  G06F11/00

Abstract: A keyboard operated programmable electronic calculator is provided with a light display and individual key lights for the numeric and function keys. A program is entered into storage by operation of the numeric and function keys when the calculator is activated to the program mode by a first control key. The program is read out of storage by operation of a second control key. Control logic under control of the calculator CPU operates the light display and the individual key lights in response to manual operation of the second control key to identify the program step and its program parameter for checking purposes.