GB1191507A - Data Processing System having Improved Arithmetic Portion Therein. - Google Patents
Data Processing System having Improved Arithmetic Portion Therein.Info
- Publication number
- GB1191507A GB1191507A GB4158267A GB4158267A GB1191507A GB 1191507 A GB1191507 A GB 1191507A GB 4158267 A GB4158267 A GB 4158267A GB 4158267 A GB4158267 A GB 4158267A GB 1191507 A GB1191507 A GB 1191507A
- Authority
- GB
- United Kingdom
- Prior art keywords
- registers
- words
- adder
- register
- memory
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F7/00—Methods or arrangements for processing data by operating upon the order or content of the data handled
- G06F7/38—Methods or arrangements for performing computations using exclusively denominational number representation, e.g. using binary, ternary, decimal representation
- G06F7/48—Methods or arrangements for performing computations using exclusively denominational number representation, e.g. using binary, ternary, decimal representation using non-contact-making devices, e.g. tube, solid state device; using unspecified devices
- G06F7/52—Multiplying; Dividing
- G06F7/535—Dividing only
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F7/00—Methods or arrangements for processing data by operating upon the order or content of the data handled
- G06F7/38—Methods or arrangements for performing computations using exclusively denominational number representation, e.g. using binary, ternary, decimal representation
- G06F7/48—Methods or arrangements for performing computations using exclusively denominational number representation, e.g. using binary, ternary, decimal representation using non-contact-making devices, e.g. tube, solid state device; using unspecified devices
- G06F7/483—Computations with numbers represented by a non-linear combination of denominational numbers, e.g. rational numbers, logarithmic number system or floating-point numbers
- G06F7/487—Multiplying; Dividing
- G06F7/4873—Dividing
Abstract
1,191,507. Data processing systems. GENERAL ELECTRIC CO. 12 Sept., 1967 [4 Oct., 1966 (2)], No. 41582/67. Heading G4A. In a data processing system including a memory for storing instruction words and data words and an arithmetic unit, the arithmetic unit includes a number of programme accessible registers for storing numbers having different significances and different instructions are available for handling the numbers according to said significances. In particular numbers are available in a variety of floating-point formats, the arrangement being such as to allow selective manipulation of the contents of these registers to achieve varying degrees of precision and flexibility in arithmetic operations, particularly division. As shown (Fig. 1), a memory 6 stores 36-bit words in a number of different floating point formats. Thus, each word may comprise an 8-bit exponent and a 28-bit mantissa or the exponents and mantissas may be stored in separate single words or the exponents may be stored in single words and the mantissa in double (adjacent) words. Data from the memory 6 may be passed by way of a switch 10 and an M-register 14 to a selected one or ones of the temporary storage registers 22, 30, 36, 40 and 56. Registers 22 (8-bits) and 30 (10-bits) are normally used for storing exponents and are associated with an adder 34 whereas registers 36, 40 and 56 (all of 72-bits) are normally used for storing mantissas and are associated with an adder 38. A counter 28 is provided for counting steps in iterative processes such as division. Instruction words, also received by way of switch 10, are retrieved from memory in pairs and passed to temporary storage register 78 for decoding by means 92, 97 and 99. Instructions are described in the Specification for accessing, manipulating (adding or dividing) and storing words representing numbers in any of the floating-point formats referred to above. Division.-Two divide instructions are provided in the first of which a dividend already loaded into registers 30 and 56 is divided by a divisor at an address specified by the address portion of the instruction (Fig. 2, not shown). In the second divide instruction, the operand already in registers 30, 56 is treated as divisor and the operand in memory as dividend. With both instructions the divide operation proper starts after normalization and with the dividend in registers 40, 30 and the divisor in registers 36, 22. If the dividend is not negative and the divisor positive, complementing of the necessary operands is effected. Division of the normalized mantissas is by repeated subtraction in adder 38 followed by shift with the G-counter 28 counting the number of iterations performed. If subtraction is successful, (carry signal SC o = 1) the output of the adder 38 is returned to the N register 40 (shifted left one position) but if subtraction is not successful (SC o = 0) the previous contents of N register 40 are merely shifted left by one position. The quotient is developed in register 56 and is complemented to provide the final result. The exponents are simply subtracted in adder 34 and complemented.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US58414366A | 1966-10-04 | 1966-10-04 | |
US58414466A | 1966-10-04 | 1966-10-04 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1191507A true GB1191507A (en) | 1970-05-13 |
Family
ID=27079011
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB4158267A Expired GB1191507A (en) | 1966-10-04 | 1967-09-12 | Data Processing System having Improved Arithmetic Portion Therein. |
Country Status (3)
Country | Link |
---|---|
DE (1) | DE1549440A1 (en) |
FR (1) | FR1557687A (en) |
GB (1) | GB1191507A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1296813C (en) * | 2002-06-20 | 2007-01-24 | 松下电器产业株式会社 | Floating-point storage method and floating-point arithmetic device |
-
1967
- 1967-09-12 GB GB4158267A patent/GB1191507A/en not_active Expired
- 1967-10-03 FR FR1557687D patent/FR1557687A/fr not_active Expired
- 1967-10-03 DE DE19671549440 patent/DE1549440A1/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1296813C (en) * | 2002-06-20 | 2007-01-24 | 松下电器产业株式会社 | Floating-point storage method and floating-point arithmetic device |
Also Published As
Publication number | Publication date |
---|---|
FR1557687A (en) | 1969-02-21 |
DE1549440A1 (en) | 1971-03-04 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PLNP | Patent lapsed through nonpayment of renewal fees |