From b29167eeee880c9f7f31194c94aadf715733bf99 Mon Sep 17 00:00:00 2001
From: iximeow <me@iximeow.net>
Date: Sat, 23 Dec 2023 19:29:20 -0800
Subject: lots of stuff. yax rx notes

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+# regmap
+
+an april fools prank but make it March. [the README says it best](https://github.com/iximeow/regmap#regmap):
+
+> `regmap` handles this design oversight by allowing users to memory-map the processor's general-purpose registers (GPR).
+
+and
+
+> # why
+> because it's funny
+
+but more seriously, [`regmap`'s emulation](https://github.com/iximeow/regmap/blob/no-gods-no-/src/regmap.rs#L442-L746) of x86 was a first draft of how i might want to describe instruction semantics like i eventually did in [`yaxpeax-core`](https://github.com/iximeow/yaxpeax-core/blob/no-gods-no-/src/arch/x86_64/semantic.rs#L266). this is where i discovered that `do_binop` and its approach, as well as `conditional_loc_write` as it eventually was written in `yaxpeax-core`, don't work as well with dead code elimination (circa 2021 Rust) as i'd wanted.
+
+and anyway, sometimes i forget that `regmap` made it possible to write this [disorienting mess of a program](https://github.com/iximeow/regmap/blob/no-gods-no-/examples/hello_world.rs):
+```
+use regmap::registers::*;
+
+fn main() {
+    unsafe { regmap::map_registers(); }
+
+    println!("rsp: {:x}", RSP.load());
+    RSP.sub_assign(8);
+    RIP.store(lol as u64);
+}
+
+fn lol() {
+    println!("very good");
+    RSP.sub_assign(8);
+    RDI.store(1);
+    RSI.store(1234);
+    RIP.store(lol_args as u64);
+}
+
+fn lol_args(a1: u64, a2: u64) {
+    println!("a1: {}, a2: {}", a1, a2);
+    println!("goodbye!");
+    std::process::exit(0);
+}
+```
+which, you guessed it (?), prints out
+```
+rsp: 0xwhatever
+very good
+a1: 1, at: 1234
+goodbye!
+```
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