Difference between revisions of "Signed"
Chris Tyler (talk | contribs) |
Chris Tyler (talk | contribs) |
||
| Line 1: | Line 1: | ||
[[Category:Computer Architecture]] | [[Category:Computer Architecture]] | ||
| − | A ''signed'' value is a binary value stored in two's compliment representation, where the most significant bit is used as a negative sign. | + | |
| + | A ''signed'' value is a binary value with a positive/negative ''sign''. | ||
| + | |||
| + | == Two's Compliment == | ||
| + | |||
| + | stored in two's compliment representation, where the most significant bit is used as a negative sign. | ||
are Signed used values | are Signed used values | ||
| Line 6: | Line 11: | ||
Signed address offsets are often used for relative [[Addressing Mode|addressing modes]]. | Signed address offsets are often used for relative [[Addressing Mode|addressing modes]]. | ||
| + | |||
| + | == BCD == | ||
| + | |||
| + | In [[BCD]], the high-order nibble is used to represent the sign (0 == positive, non-0 == negative). | ||
Revision as of 12:43, 14 January 2014
A signed value is a binary value with a positive/negative sign.
Two's Compliment
stored in two's compliment representation, where the most significant bit is used as a negative sign. are Signed used values
Example: A single unsigned byte (8 bits) stores an integer value in the range of 0 to (2^8 - 1 =) 255. If the byte is treated as a signed value, then values from 0-127 (0x00-0x7F) are treated as the positive integers 0-127, and the values 128-255 (0x80-0xFF) are treated as negative integers -128 to -1.
Signed address offsets are often used for relative addressing modes.
BCD
In BCD, the high-order nibble is used to represent the sign (0 == positive, non-0 == negative).
