Start decoupling of rendering from update passes

1 files changed, 37 insertions, 0 deletions

diff --git a/src/save.c b/src/save.c
new file mode 100644
index 0000000..45a099d
--- /dev/null
+++ b/src/save.c
@@ -0,0 +1,37 @@
+//
+// Save data.
+//
+
+typedef struct Metadata {
+    u8 blank;
+    u32 magic;
+    int current_bank;
+    int current_pattern;
+} Metadata;
+
+static Metadata metadata = {0};
+
+void
+sram_read(u8 *dst, u16 pos, u16 n_bytes) {
+    for (size_t i = 0; i < n_bytes; ++i) {
+        dst[i] = SRAM[pos + i];
+    }
+}
+
+void
+sram_write(u8 *src, u16 pos, u16 n_bytes) {
+    for (size_t i = 0; i < n_bytes; ++i) {
+        SRAM[pos + i] = src[i];
+    }
+}
+
+void
+save_bank(int i) {
+    sram_write(&patterns, sizeof(Metadata) + i * sizeof(patterns), sizeof(patterns));
+}
+
+void
+load_bank(int i) {
+    sram_read(&patterns, sizeof(Metadata) + i * sizeof(patterns), sizeof(patterns));
+}
+