Notes on caller- and callee-saved registers.

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notes/_journal/2024-11-18.md

@@ -0,0 +1,9 @@
+---
+title: "2024-11-18"
+---
+
+- [ ] Anki Flashcards
+- [x] KoL
+- [ ] OGS
+- [ ] Sheet Music (10 min.)
+- [ ] Korean (Read 1 Story)

notes/_journal/2024-11/2024-11-17.md

@@ -0,0 +1,9 @@
+---
+title: "2024-11-18"
+---
+
+- [x] Anki Flashcards
+- [x] KoL
+- [ ] OGS
+- [ ] Sheet Music (10 min.)
+- [ ] Korean (Read 1 Story)

notes/algorithms/order-growth.md

@@ -1195,7 +1195,7 @@ END%%
 %%ANKI
 Basic
 What is the reflexive property of $\omega$-notation?
-Back: N/A
+Back: N/A.
 Reference: Thomas H. Cormen et al., Introduction to Algorithms, Fourth edition (Cambridge, Massachusett: The MIT Press, 2022).
 <!--ID: 1709752223537-->
 END%%

notes/c17/types/derived.md

@@ -1026,6 +1026,62 @@ Tags: x86-64
 <!--ID: 1730740461670-->
 END%%
 
+%%ANKI
+Basic
+Suppose `char *p` has address `S`. What is the result of the following?
+```c
+(int *) p + 7
+```
+Back: `S + 28`
+Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
+<!--ID: 1731942192201-->
+END%%
+
+%%ANKI
+Basic
+Suppose `char *p` has address `S`. What is the result of the following?
+```c
+(int *) (p + 7)
+```
+Back: `S + 7`
+Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
+<!--ID: 1731942192210-->
+END%%
+
+%%ANKI
+Basic
+How do we declare a function pointer `fp` to the following?
+```c
+int foo(int x, int *p);
+```
+Back:
+```c
+int (*fp)(int, int *);
+```
+Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
+<!--ID: 1731942192213-->
+END%%
+
+%%ANKI
+Basic
+What do the following two lines declare instances of?
+```c
+int (*fp)(int, int *);
+int *fp(int, int *);
+```
+Back: The first is a function pointer. The second is a function.
+Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
+<!--ID: 1731942192218-->
+END%%
+
+%%ANKI
+Basic
+What is the value of a function pointer?
+Back: The address of the first instruction in the function's machine-code representation.
+Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
+<!--ID: 1731942192229-->
+END%%
+
 ## Bibliography
 
 * Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.

notes/encoding/floating-point.md

@@ -1325,8 +1325,8 @@ END%%
 
 %%ANKI
 Basic
-What is the most important group quality $+^f$ is lacking?
-Back: Associativity.
+What are the most important group qualities $+^f$ is lacking?
+Back: Associativity and commutativity.
 Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
 <!--ID: 1710680824824-->
 END%%

notes/hashing/addressing.md

@@ -546,7 +546,7 @@ END%%
 
 %%ANKI
 Basic
-When is the load factor of a open addressing hash table $1$?
+When does the load factor of an open addressing hash table equal $1$?
 Back: When there exist the same number of total entries as slots.
 Reference: Thomas H. Cormen et al., Introduction to Algorithms, Fourth edition (Cambridge, Massachusett: The MIT Press, 2022).
 <!--ID: 1718759188182-->

notes/set/graphs.md

@@ -961,7 +961,7 @@ END%%
 Basic
 What are the paths from vertex $3$ to vertex $6$?
 ![[directed-graph-example.png]]
-Back: N/A
+Back: N/A.
 Reference: Thomas H. Cormen et al., Introduction to Algorithms, Fourth edition (Cambridge, Massachusett: The MIT Press, 2022).
 <!--ID: 1710807788332-->
 END%%

notes/set/natural-numbers.md

@@ -291,7 +291,7 @@ END%%
 
 %%ANKI
 Basic
-What can be said about a subset of $\omega$?
+What can be said about subsets of $\omega$?
 Back: N/A.
 Reference: Herbert B. Enderton, *Elements of Set Theory* (New York: Academic Press, 1977).
 <!--ID: 1724606314394-->
@@ -299,8 +299,8 @@ END%%
 
 %%ANKI
 Basic
-What can be said about an inductive subset of $\omega$?
-Back: It must coincide with $\omega$.
+What can be said about inductive subsets of $\omega$?
+Back: They must coincide with $\omega$.
 Reference: Herbert B. Enderton, *Elements of Set Theory* (New York: Academic Press, 1977).
 <!--ID: 1724606314396-->
 END%%

notes/x86-64/registers.md

@@ -307,6 +307,54 @@ Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Program
 <!--ID: 1728558297568-->
 END%%
 
+%%ANKI
+Basic
+Which number-suffixed register(s) are used for passing integral arguments to procedures?
+Back: `%r8` and `%r9`.
+Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
+<!--ID: 1731938810848-->
+END%%
+
+%%ANKI
+Basic
+Which number-suffixed register(s) are conventionally designated "callee-saved"?
+Back: `%r12`, `%13`, `%r14`, and `%r15`.
+Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
+<!--ID: 1731938810852-->
+END%%
+
+%%ANKI
+Basic
+Which number-suffixed register(s) are conventionally designated "caller-saved"?
+Back: `%r10` and `%r11`.
+Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
+<!--ID: 1731938810854-->
+END%%
+
+%%ANKI
+Basic
+What does it mean for a register to be callee-saved?
+Back: The callee must ensure the register's value is unchanged by the time it returns.
+Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
+<!--ID: 1731938810857-->
+END%%
+
+%%ANKI
+Basic
+What does it mean for a register to be caller-saved?
+Back: Any procedure can modify the register's value.
+Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
+<!--ID: 1731938810860-->
+END%%
+
+%%ANKI
+Basic
+*Why* are caller-saved registers named the way they are?
+Back: It's up to the caller to preserve their value before a procedure call.
+Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
+<!--ID: 1731938810863-->
+END%%
+
 ## Condition Codes
 
 The CPU also maintains a set of single-bit **condition code** registers describing attributes of the most recent arithmetic or logical operation.