JIT: Naive support for 0x40 prefix, split instr decoder into separate func

diff --git a/jit/exception_handler.cpp b/jit/exception_handler.cpp
index 2672f5eb98a30fd4ff1dac2e612b45a6765df25c..c3caa59c114789e7e4898144353de39f1e574030 100644 (file)
--- a/jit/exception_handler.cpp
+++ b/jit/exception_handler.cpp
@@ -153,6 +153,94 @@ static int delete_trigger(blockinfo *bi, void *pc)
        return 0;
 }
 
+static bool decode_instruction(uae_u8 *pc, int *r, int *dir, int *size, int *len)
+{
+       *r = -1;
+       *size = 4;
+       *dir = -1;
+       *len = 0;
+
+#ifdef CPU_x86_64
+       if (*pc == 0x67) {
+               /* Skip address-size override prefix */
+               pc += 1;
+               *len += 1;
+       }
+       if (*pc == 0x40) {
+               /* Skip REX prefix */
+               pc += 1;
+               *len += 1;
+       }
+#endif
+       if (*pc == 0x66) {
+               pc += 1;
+               *size = 2;
+               *len += 1;
+       }
+
+       switch (pc[0]) {
+       case 0x8a:
+               if ((pc[1] & 0xc0) == 0x80) {
+                       *r = (pc[1] >> 3) & 7;
+                       *dir = SIG_READ;
+                       *size = 1;
+                       *len += 6;
+                       break;
+               }
+               break;
+       case 0x88:
+               if ((pc[1] & 0xc0) == 0x80) {
+                       *r = (pc[1] >> 3) & 7;
+                       *dir = SIG_WRITE;
+                       *size = 1;
+                       *len += 6;
+                       break;
+               }
+               break;
+       case 0x8b:
+               switch (pc[1] & 0xc0) {
+               case 0x80:
+                       *r = (pc[1] >> 3) & 7;
+                       *dir = SIG_READ;
+                       *len += 6;
+                       break;
+               case 0x40:
+                       *r = (pc[1] >> 3) & 7;
+                       *dir = SIG_READ;
+                       *len += 3;
+                       break;
+               case 0x00:
+                       *r = (pc[1] >> 3) & 7;
+                       *dir = SIG_READ;
+                       *len += 2;
+                       break;
+               default:
+                       break;
+               }
+               break;
+       case 0x89:
+               switch (pc[1]&0xc0) {
+               case 0x80:
+                       *r = (pc[1] >> 3) & 7;
+                       *dir = SIG_WRITE;
+                       *len += 6;
+                       break;
+               case 0x40:
+                       *r = (pc[1] >> 3) & 7;
+                       *dir = SIG_WRITE;
+                       *len += 3;
+                       break;
+               case 0x00:
+                       *r = (pc[1] >> 3) & 7;
+                       *dir = SIG_WRITE;
+                       *len += 2;
+                       break;
+               }
+               break;
+       }
+       return r != 0;
+}
+
 #ifdef HAVE_CONTEXT_T
 /*
  * Try to handle faulted memory access in compiled code
@@ -188,80 +276,7 @@ static int handle_access(uintptr_t fault_addr, CONTEXT_T context)
                write_log (_T("JIT: Argh --- Am already in a handler. Shouldn't happen!\n"));
 
        if (canbang && fault_pc >= compiled_code && fault_pc <= current_compile_p) {
-               uae_u8 *pc = fault_pc;
-#ifdef CPU_x86_64
-               if (*pc == 0x67) {
-                       /* Skip address-size override prefix */
-                       pc++;
-                       len++;
-               }
-#endif
-               if (*pc == 0x66) {
-                       pc++;
-                       size = 2;
-                       len++;
-               }
-
-               switch (pc[0]) {
-               case 0x8a:
-                       if ((pc[1]&0xc0)==0x80) {
-                               r=(pc[1]>>3)&7;
-                               dir=SIG_READ;
-                               size=1;
-                               len+=6;
-                               break;
-                       }
-                       break;
-               case 0x88:
-                       if ((pc[1]&0xc0)==0x80) {
-                               r=(pc[1]>>3)&7;
-                               dir=SIG_WRITE;
-                               size=1;
-                               len+=6;
-                               break;
-                       }
-                       break;
-               case 0x8b:
-                       switch (pc[1]&0xc0) {
-                       case 0x80:
-                               r=(pc[1]>>3)&7;
-                               dir=SIG_READ;
-                               len+=6;
-                               break;
-                       case 0x40:
-                               r=(pc[1]>>3)&7;
-                               dir=SIG_READ;
-                               len+=3;
-                               break;
-                       case 0x00:
-                               r=(pc[1]>>3)&7;
-                               dir=SIG_READ;
-                               len+=2;
-                               break;
-                       default:
-                               break;
-                       }
-                       break;
-               case 0x89:
-                       switch (pc[1]&0xc0) {
-                       case 0x80:
-                               r=(pc[1]>>3)&7;
-                               dir=SIG_WRITE;
-                               len+=6;
-                               break;
-                       case 0x40:
-                               r=(pc[1]>>3)&7;
-                               dir=SIG_WRITE;
-                               len+=3;
-                               break;
-                       case 0x00:
-                               r=(pc[1]>>3)&7;
-                               dir=SIG_WRITE;
-                               len+=2;
-                               break;
-                       }
-                       break;
-               }
+               decode_instruction(fault_pc, &r, &dir, &size, &len);
        }
 
        if (r!=-1) {
@@ -432,8 +447,18 @@ static void sigsegv_handler(int signum, siginfo_t *info, void *context)
 
 #endif
 
+// #define TEST_EXCEPTION_HANDLER
+
+#ifdef TEST_EXCEPTION_HANDLER
+#include "test_exception_handler.cpp"
+#endif
+
 static void install_exception_handler(void)
 {
+#ifdef TEST_EXCEPTION_HANDLER
+       test_exception_handler();
+#endif
+
 #ifdef JIT_EXCEPTION_HANDLER
        if (veccode == NULL) {
                veccode = (uae_u8 *) uae_vm_alloc(256, UAE_VM_32BIT, UAE_VM_READ_WRITE_EXECUTE);