fixing lec + adding lec4 base: TODO<all of lec4>

cst337/lec/lec3.md

@@ -1,21 +1,31 @@
 # lec3
 
-> Conceptual things
-
-Until the technical lectures really start, I'll be feeding in a few technical things here and there for the sake of getting used to them.
-
 ## One's & Two's Complement
+
 _Previous lecture went over signedness of numbers so this section won't as much_.
-One's complement in xor(just flip)
-> xor 0xFF, target
+
+First we'll deal with flipping bits: this is where you may hear the term _1's complement_.
+While not very useful on it's own for most purposes it does help get closer to creating a seperation between _positive_ and _negative_ numbers.
+
+The only other step after flipping all the bits is just adding 1.
+
+`1001 1110` becomes `0110 0010`.
+
+> shouldn't that last 2 bits be 01?
+
+Close, the reason why we have `b10` is because if we: `b01 + b1` the `1` will carry over to the next bit.
+The actual term for this is just __negate__; the other way around is essentially cannon fodder.
+
+>Ok, but what does that look like _assembly_ the thing I came here to learn.
+
+Most assemblers accept something like `neg targetValue` however you can also use an _exclusive or_[`xor targetValue, 0xFF`]. Keep in mind that the immediate value should be sign-extended to reflect the proper targetValue size.
 
 Two's complement proccess:
 1. Flips bits
 2. Add 1
 
-The actual term for this is just __negate__; the other way around is essentially cannon fodder.
-
 ## Sign Flag 
+
 Set whenever we produce (any) number where the leading bit is set(1).
 Regardless if we're dealing with signed or unsigned data.
 

cst337/lec/lec4.md

@@ -0,0 +1,9 @@
+# lec4
+
+_this page to be updated late since i just got lazy this time_
+Topics to cover:
+* add/sub
+* intro to overflows
+* intro to carries
+* translating this to some 64 bit add/sub instructions and becoming more familiar with the flags register
+	* eflags won't be covered indepth yet but merely mentioned for sake of preparative clarity