1. Field of the Invention
The present invention relates to electronic equipment capable of arithmetic operations.
2. Description of the Prior Art
Prior art electronic calculators generally have one display panel on which numeric data entered first (to be referred to as "a first operand" in this specification), numeric data entered second (to be referred to as "a second operand" in this specification) and a result of an arithmetic operation of the first and second operands are sequentially displayed one by one in the order named. As a result, when an operator suspends and then restarts arithmetic operations, he may not identify very frequently whether the numeric data being displayed is a first or second operand or a result and, if it is the result, by what arithmetic operation this result has been obtained.
Furthermore with prior art electronic calculators with a so-called independent memory, the contents thereof is in general not displayed so that the operator must depress a key in order to fetch and display the contents of the independent memory.
The power consumption of the arithmetic-logic units, memories, registers and so on in the electronic calculators has been recently drastically reduced because of the rapid development of the semiconductor device technology, but the power consumption of display panels is still high. Therefore, the batteries of a battery-operated electronic pocket type calculator or the like must be changed at a relatively short interval of time.
There has been devised and demonstrated an electronic calculator capable of itemizing or recording the number of arithmetic operations executed by the operation of a switch or the like, but the operation is very cumbersome and inconvenient.
In general, small electronic calculators include 8-digit registers and an 8-array display panel for displaying 8-digit numeric data, but it occurs very often that the number of digits of the result from the operation of the first and second operands exceeds eight digits so that the total digits of result the cannot be displayed on the display panel. In order to solve this overflow problem, there have been proposed and demonstrated the following three display methods:
______________________________________ 1. " E 0 ", 2. " E 7 6 9.2 5 9 2 5 ", and 3. " 7 6 9.2 5 9 2 5 " depress " P " key, and then " 8 4 8.0 0 0 0 0 0 ". ______________________________________
The first method does not display the result at all. The second method omits some lower digits, and the operator cannot identify how many lower digits are omitted. According to the third method, the result is stored in two registers. Upon depression of the "equal" key, the higher digits bits of the result are displayed and upon a subsequent depression of the key "P", the lower digits are displayed. As a result, the operator cannot see the result at one glance, and the keying operation is complex.