EnvFlags OK (#404)

* Matched

* Remove magic number

* Rename system to EnvFlags

src/code/z_env_flags.c

@@ -0,0 +1,33 @@
+#include "global.h"
+
+void EnvFlags_UnsetAll(GlobalContext* globalCtx) {
+    u8 i;
+
+    for (i = 0; i < ARRAY_COUNT(globalCtx->envFlags); i++) {
+        globalCtx->envFlags[i] = 0;
+    }
+}
+
+void EnvFlags_Set(GlobalContext* globalCtx, s16 flag) {
+    s16 index = flag / 16;
+    s16 bit = flag % 16;
+    s16 mask = 1 << bit;
+
+    globalCtx->envFlags[index] |= mask;
+}
+
+void EnvFlags_Unset(GlobalContext* globalCtx, s16 flag) {
+    s16 index = flag / 16;
+    s16 bit = flag % 16;
+    s16 mask = (1 << bit) ^ 0xFFFF;
+
+    globalCtx->envFlags[index] &= mask;
+}
+
+s32 EnvFlags_Get(GlobalContext* globalCtx, s16 flag) {
+    s16 index = flag / 16;
+    s16 bit = flag % 16;
+    s16 mask = 1 << bit;
+
+    return globalCtx->envFlags[index] & mask;
+}