Negative flag
In this article, we will explore the topic of Negative flag from a multidimensional perspective, analyzing its implications in different contexts and its relevance today. We will delve into its origins, evolution and its impact on society, as well as the challenges and opportunities it presents. Through a detailed analysis, we will seek to unravel the different facets of Negative flag and its influence in various areas, in order to provide a comprehensive vision that allows us to understand its complexity and scope. From its historical aspects to its future projections, this article aims to offer a comprehensive and enriching vision of Negative flag, inviting the reader to reflect and question their own perception of this topic.
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In a computer processor the negative flag or sign flag is a single bit in a system status (flag) register used to indicate whether the result of the last mathematical operation produced a value in which the most significant bit (the left most bit) was set. In a two's complement interpretation of the result, the negative flag is set if the result was negative.
For example, in an 8-bit signed number system, -37 will be represented as 1101 1011 in binary (the most significant bit, or sign bit, is 1), while +37 will be represented as 0010 0101 (the most significant bit is 0).
The negative flag is set according to the result in the x86 series processors by the following instructions (referring to the Intel 80386 manual[1]):
- All arithmetic operations except multiplication and division;
- compare instructions (equivalent to subtract instructions without storing the result);
- Logical instructions – XOR, AND, OR;
- TEST instructions (equivalent to AND instructions without storing the result).