Difference between revisions of "Assembly Language Twos Complement"
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==Explanation== | ==Explanation== | ||
| − | Line 1 will get a value | + | Line 1 will get a value to use, and store it in Register 0. |
Line 2 will perform a Bitwise NOT on the value in Register 0, and store it in Register 1. | Line 2 will perform a Bitwise NOT on the value in Register 0, and store it in Register 1. | ||
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Line 3 will Add #1 to the value in Register 1, and store it in Register 1. | Line 3 will Add #1 to the value in Register 1, and store it in Register 1. | ||
| − | + | The answer will be stored in Register 1. | |
Latest revision as of 12:19, 21 January 2020
You can use a Bitwise NOT to flip all of the bits in a register, ie a binary digit of 0 becomes 1 and so on. We can use this to write a program to convert numbers to Two's Complement:
Program
mov r0, #20 mvn r1,r0 add r1,r1,#1
Explanation
Line 1 will get a value to use, and store it in Register 0.
Line 2 will perform a Bitwise NOT on the value in Register 0, and store it in Register 1.
Line 3 will Add #1 to the value in Register 1, and store it in Register 1.
The answer will be stored in Register 1.
