From: Rune Holm <rune.holm@gmail.com>
Date: Fri, 11 Jun 2021 18:34:03 +0000 (+0100)
Subject: pull the PC masking into the code translation cache, so that we only need to mask... 
X-Git-Url: https://git.sesse.net/?a=commitdiff_plain;h=fe3b4bb032e02148c44ea11a23129650eae7efd7;p=pistorm

pull the PC masking into the code translation cache, so that we only need to mask the PC on our slow path. Gives us another 5-10% speedup.
---

diff --git a/m68kcpu.c b/m68kcpu.c
index 4a4fc39..da93430 100644
--- a/m68kcpu.c
+++ b/m68kcpu.c
@@ -1254,12 +1254,14 @@ inline unsigned int  m68k_read_pcrelative_32(unsigned int address) {
 #endif
 
 
-uint m68ki_read_imm6_addr_slowpath(uint32_t address, address_translation_cache *cache)
+uint m68ki_read_imm6_addr_slowpath(uint32_t pc, address_translation_cache *cache)
 {
+    uint32_t address = ADDRESS_68K(pc);
+    uint32_t pc_address_diff = pc - address;
 	for (int i = 0; i < read_ranges; i++) {
 		if(address >= read_addr[i] && address < read_upper[i]) {
-            cache->lower = read_addr[i];
-            cache->upper = read_upper[i];
+            cache->lower = read_addr[i] + pc_address_diff;
+            cache->upper = read_upper[i] + pc_address_diff;
             cache->data = read_data[i];
 			REG_PC += 2;
 			return be16toh(((unsigned short *)(read_data[i] + (address - read_addr[i])))[0]);
diff --git a/m68kcpu.h b/m68kcpu.h
index 38d6b9f..21d11ad 100644
--- a/m68kcpu.h
+++ b/m68kcpu.h
@@ -1161,21 +1161,21 @@ static inline uint32 m68ki_ic_readimm16(uint32 address)
 /* Handles all immediate reads, does address error check, function code setting,
  * and prefetching if they are enabled in m68kconf.h
  */
-uint m68ki_read_imm6_addr_slowpath(uint32_t address, address_translation_cache *cache);
+uint m68ki_read_imm6_addr_slowpath(uint32_t pc, address_translation_cache *cache);
 
 
 
 static inline uint m68ki_read_imm_16(void)
 {
-	uint32_t address = ADDRESS_68K(REG_PC);
+	uint32_t pc = REG_PC;
 
     address_translation_cache *cache = &code_translation_cache;
-    if(address >= cache->lower && address < cache->upper)
+    if(pc >= cache->lower && pc < cache->upper)
     {
         REG_PC += 2;
-        return be16toh(((unsigned short *)(cache->data + (address - cache->lower)))[0]);
+        return be16toh(((unsigned short *)(cache->data + (pc - cache->lower)))[0]);
     }
-    return m68ki_read_imm6_addr_slowpath(address, cache);
+    return m68ki_read_imm6_addr_slowpath(pc, cache);
 }