better target name

README.md

@@ -30,7 +30,7 @@ do this stuff.
    dots as well as other support files:
   * crt0.s
   * linker.ld
-  * thumbv4-none-eabi.json
+  * thumbv4-nintendo-agb.json
   * build.rs
 
 5) Run `arm-none-eabi-as crt0.s -o crt0.o` to build the `crt0.s` into a `crt0.o`
@@ -38,7 +38,7 @@ do this stuff.
    `build.bat` file it's set to simply run every single time because it's a
    cheap enough operation.
 
-6) Build with `cargo xbuild --target thumbv4-none-eabi.json`
+6) Build with `cargo xbuild --target thumbv4-nintendo-agb.json`
   * The file extension is significant, and `cargo xbuild` takes it as a flag to
     compile dependencies with the same sysroot, so you can include crates
     normally. Well, crates that can run inside a GBA at least (Which means they
@@ -47,7 +47,7 @@ do this stuff.
     helpful because it has debug symbols).
 
 7) Also you can patch up the output to be a "real" ROM file:
-  * `arm-none-eabi-objcopy -O binary target/thumbv4-none-eabi/debug/gbatest target/output.gba`
+  * `arm-none-eabi-objcopy -O binary target/thumbv4-nintendo-agb/debug/gbatest target/output.gba`
   * `gbafix target/output.gba`
 
 8) Alternately, you can use the provided `build.bat` file (or write a similar

book/src/ch0/index.md

@@ -37,8 +37,10 @@ Now you'll need some particular files each time you want to start a new project.
 You can find them in the root of the [rust-console/gba
 repo](https://github.com/rust-console/gba).
 
-* `thumbv4-none-eabi.json` describes the overall GBA to cargo-xbuild so it knows
-  what to do.
+* `thumbv4-nintendo-agb.json` describes the overall GBA to cargo-xbuild so it
+  knows what to do. This is actually a somewhat made up target name since
+  there's no official target name, but this is the best name to pick based on
+  [how target names are decided](https://wiki.osdev.org/Target_Triplet).
 * `crt0.s` describes some ASM startup stuff. If you have more ASM to place here
   later on this is where you can put it. You also need to build it into a
   `crt0.o` file before it can actually be used, but we'll cover that below.
@@ -55,7 +57,7 @@ Once you've got something to build, you perform the following steps:
     might as well do it every time so that you never forget to because it's a
     practically instant operation.
 
-* `cargo xbuild --target thumbv4-none-eabi.json`
+* `cargo xbuild --target thumbv4-nintendo-agb.json`
   * This builds your Rust source. It accepts _most of_ the normal options, such
     as `--release`, and options, such as `--bin foo` or `--examples`, that you'd
     expect `cargo` to accept.
@@ -81,7 +83,7 @@ emulators can also do it.
 However, if you want a "real" ROM that works in all emulators and that you could
 transfer to a flash cart there's a little more to do.
 
-* `arm-none-eabi-objcopy -O binary target/thumbv4-none-eabi/MODE/BIN_NAME target/ROM_NAME.gba`
+* `arm-none-eabi-objcopy -O binary target/thumbv4-nintendo-agb/MODE/BIN_NAME target/ROM_NAME.gba`
   * This will perform an [objcopy](https://linux.die.net/man/1/objcopy) on our
     program. Here I've named the program `arm-none-eabi-objcopy`, which is what
     devkitpro calls their version of `objcopy` that's specific to the GBA in the
@@ -95,7 +97,7 @@ transfer to a flash cart there's a little more to do.
     `cargo` arranges stuff in the `target/` directory, and between RLS and
     `cargo doc` and stuff it gets kinda crowded, so it goes like this:
     * Since our program was built for a non-local target, first we've got a
-      directory named for that target, `thumbv4-none-eabi/`
+      directory named for that target, `thumbv4-nintendo-agb/`
     * Next, the "MODE" is either `debug/` or `release/`, depending on if we had
       the `--release` flag included. You'll probably only be packing release
       mode programs all the way into GBA roms, but it works with either mode.

book/src/ch1/the_display_control.md

@@ -43,9 +43,11 @@ locations on the screen.
 
 ## CGB Mode
 
-Bit 3 is read only. It's on if you're running in CGB mode. Since we're making
-GBA games you'd think that it'll never be on at all, but I guess you can change
-it with BIOS stuff. Still, basically not an important bit.
+Bit 3 is effectively read only. Technically it can be flipped using a BIOS call,
+but when you write to the display control normally it won't write to this bit,
+so we'll call it effectively read only.
+
+This bit is on if the CPU is in CGB mode.
 
 ## Page Flipping
 

build.bat

@@ -3,12 +3,12 @@
 arm-none-eabi-as crt0.s -o crt0.o
 
 @rem Build all examples, both debug and release
-cargo xbuild --examples --target thumbv4-none-eabi.json
-cargo xbuild --examples --target thumbv4-none-eabi.json --release
+cargo xbuild --examples --target thumbv4-nintendo-agb.json
+cargo xbuild --examples --target thumbv4-nintendo-agb.json --release
 
 @echo Packing examples into ROM files...
 @for %%I in (.\examples\*.*) do @(
   echo %%~nI
-  arm-none-eabi-objcopy -O binary target/thumbv4-none-eabi/release/examples/%%~nI target/example-%%~nI.gba >nul
+  arm-none-eabi-objcopy -O binary target/thumbv4-nintendo-agb/release/examples/%%~nI target/example-%%~nI.gba >nul
   gbafix target/example-%%~nI.gba >nul
 )

docs/ch0/index.html

@@ -169,7 +169,7 @@ cargo will figure it all out for you.</p>
 You can find them in the root of the <a href="https://github.com/rust-console/gba">rust-console/gba
 repo</a>.</p>
 <ul>
-<li><code>thumbv4-none-eabi.json</code> describes the overall GBA to cargo-xbuild so it knows
+<li><code>thumbv4-nintendo-agb.json</code> describes the overall GBA to cargo-xbuild so it knows
 what to do.</li>
 <li><code>crt0.s</code> describes some ASM startup stuff. If you have more ASM to place here
 later on this is where you can put it. You also need to build it into a
@@ -190,7 +190,7 @@ practically instant operation.</li>
 </ul>
 </li>
 <li>
-<p><code>cargo xbuild --target thumbv4-none-eabi.json</code></p>
+<p><code>cargo xbuild --target thumbv4-nintendo-agb.json</code></p>
 <ul>
 <li>This builds your Rust source. It accepts <em>most of</em> the normal options, such
 as <code>--release</code>, and options, such as <code>--bin foo</code> or <code>--examples</code>, that you'd
@@ -219,7 +219,7 @@ emulators can also do it.</p>
 transfer to a flash cart there's a little more to do.</p>
 <ul>
 <li>
-<p><code>arm-none-eabi-objcopy -O binary target/thumbv4-none-eabi/MODE/BIN_NAME target/ROM_NAME.gba</code></p>
+<p><code>arm-none-eabi-objcopy -O binary target/thumbv4-nintendo-agb/MODE/BIN_NAME target/ROM_NAME.gba</code></p>
 <ul>
 <li>This will perform an <a href="https://linux.die.net/man/1/objcopy">objcopy</a> on our
 program. Here I've named the program <code>arm-none-eabi-objcopy</code>, which is what
@@ -235,7 +235,7 @@ bare memory dump of the program.</li>
 <code>cargo doc</code> and stuff it gets kinda crowded, so it goes like this:
 <ul>
 <li>Since our program was built for a non-local target, first we've got a
-directory named for that target, <code>thumbv4-none-eabi/</code></li>
+directory named for that target, <code>thumbv4-nintendo-agb/</code></li>
 <li>Next, the &quot;MODE&quot; is either <code>debug/</code> or <code>release/</code>, depending on if we had
 the <code>--release</code> flag included. You'll probably only be packing release
 mode programs all the way into GBA roms, but it works with either mode.</li>

docs/print.html

@@ -181,7 +181,7 @@ cargo will figure it all out for you.</p>
 You can find them in the root of the <a href="https://github.com/rust-console/gba">rust-console/gba
 repo</a>.</p>
 <ul>
-<li><code>thumbv4-none-eabi.json</code> describes the overall GBA to cargo-xbuild so it knows
+<li><code>thumbv4-nintendo-agb.json</code> describes the overall GBA to cargo-xbuild so it knows
 what to do.</li>
 <li><code>crt0.s</code> describes some ASM startup stuff. If you have more ASM to place here
 later on this is where you can put it. You also need to build it into a
@@ -202,7 +202,7 @@ practically instant operation.</li>
 </ul>
 </li>
 <li>
-<p><code>cargo xbuild --target thumbv4-none-eabi.json</code></p>
+<p><code>cargo xbuild --target thumbv4-nintendo-agb.json</code></p>
 <ul>
 <li>This builds your Rust source. It accepts <em>most of</em> the normal options, such
 as <code>--release</code>, and options, such as <code>--bin foo</code> or <code>--examples</code>, that you'd
@@ -231,7 +231,7 @@ emulators can also do it.</p>
 transfer to a flash cart there's a little more to do.</p>
 <ul>
 <li>
-<p><code>arm-none-eabi-objcopy -O binary target/thumbv4-none-eabi/MODE/BIN_NAME target/ROM_NAME.gba</code></p>
+<p><code>arm-none-eabi-objcopy -O binary target/thumbv4-nintendo-agb/MODE/BIN_NAME target/ROM_NAME.gba</code></p>
 <ul>
 <li>This will perform an <a href="https://linux.die.net/man/1/objcopy">objcopy</a> on our
 program. Here I've named the program <code>arm-none-eabi-objcopy</code>, which is what
@@ -247,7 +247,7 @@ bare memory dump of the program.</li>
 <code>cargo doc</code> and stuff it gets kinda crowded, so it goes like this:
 <ul>
 <li>Since our program was built for a non-local target, first we've got a
-directory named for that target, <code>thumbv4-none-eabi/</code></li>
+directory named for that target, <code>thumbv4-nintendo-agb/</code></li>
 <li>Next, the &quot;MODE&quot; is either <code>debug/</code> or <code>release/</code>, depending on if we had
 the <code>--release</code> flag included. You'll probably only be packing release
 mode programs all the way into GBA roms, but it works with either mode.</li>

thumbv4-nintendo-agb.json

@@ -18,7 +18,7 @@
   "linker": "arm-none-eabi-ld",
   "linker-flavor": "ld",
   "linker-is-gnu": true,
-  "llvm-target": "thumbv4-none-eabi",
+  "llvm-target": "thumbv4-nintendo-agb",
   "os": "none",
   "panic-strategy": "abort",
   "pre-link-args": {