Difference between revisions of "Assembly Language Twos Complement"
(→Program) |
(→Explanation) |
||
| (One intermediate revision by the same user not shown) | |||
| Line 2: | Line 2: | ||
==Program== | ==Program== | ||
| − | + | mov r0, #20 | |
mvn r1,r0 | mvn r1,r0 | ||
add r1,r1,#1 | add r1,r1,#1 | ||
| − | |||
==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. | ||
| Line 14: | Line 13: | ||
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.
