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Перевод: operand
[существительное] объект ; объект действия; операнд
Тезаурус:
- Because there is no word mark bit, the length of each operand is specified or implied in the instructions which manipulate it, which means that there is an upper limit to the length of such operands.
- The operands may be of different lengths; if the first operand is shorter, the computer processes it as if it was extended on the left with zeros; if the second (destination) field is shorter, some of the more significant digits of the result are lost.
- For example, the add instruction adds two numeric operands in the above format, leaving the result in place of the second operand.
- Each operand is a computer word (either in the accumulator or a store location), made up of a fixed number of decimal digits.
- Although most processing of arithmetic fields is from right to left, the operand is specified by the address of its left-hand byte; since the instruction specifies the length of each packed decimal operand, the address of the right-hand byte is easily obtained.
- Each operand is a string of one or more consecutive characters.
- The selected portion is aligned with the least-significant portion of the other operand (held in a processor register), and sign extension may or may not be applied (depending on the size of the portion and the value in the selection field).
- (b) Certain portions of a computer word have special significance for particular data-types: for example the exponent field of a floating-point number, and the operand field of an instruction.
- It is still not clear whether the PowerPC has had the multi-processing guts ripped out of it, though Michael Slater editor of Microprocessor Report informs us modifications made to it include having 38 opcodes deleted, which means that all instructions that use multiply and quotient register, difference or zero and three integer operand instructions have all been wiped out.
- Sometimes we will wish to use the add instruction without modification by the index register, so we need an extra bit set aside in all such instructions, to specify whether or not the modification of the operand field by means of the index register is to take place.
- In order to facilitate arithmetic, an operand is specified by the address of its right-hand (least-significant) character, and the left-hand (most-significant) character of the operand is indicated by having its word mark bit set to one.
- Three instruction formats are used; a 1-byte format with just an operation code (for example clear accumulator), a 2-byte format with an operation code and a 1-byte operand field (for example load into accumulator the value in the second byte of the instruction), and a 3-byte format with an operation code and a 2-byte operand field (for example load into accumulator the contents of the byte whose address is given by the second and third bytes of the instruction).
- On the CDC 6600 computer certain values of the floating-point exponent are set aside to represent zero, infinite, and indefinite operand values, and rules are given for arithmetic operations on these quantities (for example, the difference of two infinite operands is indefinite).
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