From a3efa633617f7b02a91348110457755de281c863 Mon Sep 17 00:00:00 2001
From: Matthew Laux <matthew.laux@gmail.com>
Date: Wed, 18 Oct 2023 17:52:24 -0500
Subject: [PATCH] no idea how to write a JIT compiler but this seems like an ok
 start

---
 src/compiler68k.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 src/compiler68k.c

diff --git a/src/compiler68k.c b/src/compiler68k.c
new file mode 100644
index 0000000..1f19c97
--- /dev/null
+++ b/src/compiler68k.c
@@ -0,0 +1,66 @@
+#include <stdint.h>
+#include <stddef.h>
+#include <stdlib.h>
+
+
+uint8_t out_code[1024];
+uint8_t memory[1024]; // ???
+uint32_t out_ptr;
+
+struct basic_block {
+    // in 68k space?
+    void *start_address;
+    size_t length;
+};
+
+// need some kind of map from gb address to struct basic_block?
+
+uint8_t test_code[] = {
+    0
+};
+
+struct basic_block *compile_block(uint16_t src_address, uint8_t *gb_code)
+{
+    uint32_t start = out_ptr;
+    struct basic_block *bblock;
+
+    bblock = malloc(sizeof *bblock);
+    bblock->start_address = out_code + start;
+
+    return bblock;
+}
+
+void run_block(struct basic_block *bblock)
+{
+    // calling convention? do i need to do this from asm?
+    uint16_t jump_target = ((uint16_t (*)()) bblock->start_address)();
+}
+
+// TODO
+void block_cache_add(uint16_t src_address, struct basic_block *bblock);
+struct basic_block *block_cache_get(uint16_t src_address);
+
+// 1. compile each block ending in a jump
+// 2. turn the jump into a return
+// 3. add the compiled code to some kind of cache
+// 3. return back to check the cache and maybe compile the next block
+
+int main(int argc, char *argv[])
+{
+    struct basic_block *bblock;
+    
+    bblock = compile_block(0, test_code);
+    block_cache_add(0, bblock);
+
+    while (1) {
+        uint16_t jump_target;
+
+        jump_target = ((uint16_t (*)()) bblock->start_address)();
+
+        bblock = block_cache_get(jump_target);
+        if (!bblock) {
+            bblock = compile_block(jump_target, test_code + jump_target);
+        }
+    }
+    return 0;
+}
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