Difference between revisions of "Signed"
From Sonic Retro
m (Negatives do start at $80, but $80 equals -$80, not -$7F.) |
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| + | When using the signed hexadecimal number system in programming (such as [[68000]] assembly), the values '''$80''' to '''$FF''' are interpreted as '''-$80''' to '''-$01''' respectively. This is because there is no way to literally prefix a number with the minus symbol "-". Instead, the highest [[bit]] in a byte is used to represent negativity. | ||
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| + | Conversely, the '''unsigned''' number system has no negatives. So '''$81''' is read simply as '''$81'''. | ||
[[Category: Hacking Information]] | [[Category: Hacking Information]] | ||
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Revision as of 11:23, 18 June 2006
When using the signed hexadecimal number system in programming (such as 68000 assembly), the values $80 to $FF are interpreted as -$80 to -$01 respectively. This is because there is no way to literally prefix a number with the minus symbol "-". Instead, the highest bit in a byte is used to represent negativity.
Conversely, the unsigned number system has no negatives. So $81 is read simply as $81.