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--- gba:guide:memory_management [2024/05/07 19:15] – created asie
+++ gba:guide:memory_management [2024/05/08 03:52] (current) – asie
@@ Line 1: / Line 1: @@
 ====== Linking and memory management ======
-===== wf-gbatool link =====
+===== Using wf-gbatool link =====
 In Wonderful's ecosystem, instead of relying on the linker and a post-link tool, linker wrappers are utilized instead. This allows handling everything from object linking to program file output in one step on the user side, as well as implementing high-level configuration facilities which generate a link script.
@@ Line 10: / Line 10: @@
   # ...becomes:
   $ wf-gbatool link rom|multiboot -o program.gba --output-elf program.elf -- [objects...] [flags...]
+  # By default, wfconfig.toml in the current working directory is used
+  # (see below). To use a different file:
+  $ wf-gbatool link rom|multiboot -c other_wfconfig.toml -o program.gba --output-elf program.elf -- [objects...] [flags...]
-===== Cartridge output configuration =====
+===== Cartridge metadata =====
 GBA cartridges contain some user-configurable metadata. To edit it, create a ''wfconfig.toml'' file with the following contents:
@@ Line 21: / Line 25: @@
 code = "XXXX"
 maker = "WF"
+</code>
+===== Default memory placement =====
+The GBA contains two separate blocks of memory: 32 kilobytes of fast IWRAM and 256 kilobytes of slower EWRAM. In Wonderful's GBA target, memory which is not explicitly marked as belonging to IWRAM or EWRAM with a section attribute is placed in EWRAM by default. However, this can be changed to IWRAM by using he following wfconfig.toml configuration:
+<code TOML>
+[memory]
+data-region = "iwram"
 </code>
@@ Line 61: / Line 74: @@
 // EWRAM is also supported!
 #define gba_overlay_load_ewram(NAME) gba_overlay_load(ewram, NAME)
+</code>
+From there, the helper can be used as follows:
+<code C>
+__attribute__((noinline, section(".iwram_one"))) void func_a(void) {
+    // ...code...
+}
+__attribute__((noinline, section(".iwram_four"))) void func_b(void) {
+    // ...code...
+}
+// ...function...
+    gba_overlay_load_iwram(one);
+    func_a();
+    gba_overlay_load_iwram(four);
+    func_b();
 </code>