From 36ce9c07e65a3f42e74f8b27f845219438a6db83 Mon Sep 17 00:00:00 2001
From: gbeauche <>
Date: Thu, 27 Nov 2003 00:26:35 +0000
Subject: [PATCH] Statically allocate the translation cache on PowerPC. This
 makes it possible to generate direct bl instructions for function invokation.

---
 SheepShaver/src/Unix/configure.in             | 28 +++++++++++++++++++
 .../src/kpx_cpu/src/cpu/jit/jit-cache.cpp     | 28 +++++++++++++++++--
 .../src/kpx_cpu/src/cpu/jit/jit-cache.hpp     |  2 ++
 3 files changed, 55 insertions(+), 3 deletions(-)

diff --git a/SheepShaver/src/Unix/configure.in b/SheepShaver/src/Unix/configure.in
index 3242af42..75f80d1e 100644
--- a/SheepShaver/src/Unix/configure.in
+++ b/SheepShaver/src/Unix/configure.in
@@ -606,6 +606,34 @@ if [[ "x$EMULATED_PPC" = "xyes" ]]; then
   fi
   CPUSRCS="$CPUSRCS ../kpx_cpu/sheepshaver_glue.cpp"
 fi
+if [[ "x$ac_cv_use_dyngen" = "xyes" ]]; then
+  AC_CACHE_CHECK([whether static data regions are executable],
+    ac_cv_have_static_data_exec, [
+    AC_TRY_RUN([int main(void) {
+#if defined(__powerpc__)
+      static unsigned int p[8] = {0x4e800020,};
+      asm volatile("dcbst 0,%0" : : "r" (p) : "memory");
+      asm volatile("sync" : : : "memory");
+      asm volatile("icbi 0,%0" : : "r" (p) : "memory");
+      asm volatile("sync" : : : "memory");
+      asm volatile("isync" : : : "memory");
+      ((void (*)(void))p)();
+      return 0;
+#endif
+#if defined(__i386__)
+      static unsigned char p[] = {0xc3};
+      ((void (*)(void))p)();
+      return 0;
+#endif
+      return 1;
+    }], ac_cv_have_static_data_exec=yes, ac_cv_have_static_data_exec=no,
+    dnl When cross-compiling, do not assume anything.
+    ac_cv_have_static_data_exec=no
+    )
+  ])
+fi
+AC_TRANSLATE_DEFINE(HAVE_STATIC_DATA_EXEC, "$ac_cv_have_static_data_exec",
+  [Define if your system marks static data pages as executable.])
 
 dnl Generate Makefile.
 AC_SUBST(DYNGENSRCS)
diff --git a/SheepShaver/src/kpx_cpu/src/cpu/jit/jit-cache.cpp b/SheepShaver/src/kpx_cpu/src/cpu/jit/jit-cache.cpp
index 3c57d3b9..4ac223e0 100644
--- a/SheepShaver/src/kpx_cpu/src/cpu/jit/jit-cache.cpp
+++ b/SheepShaver/src/kpx_cpu/src/cpu/jit/jit-cache.cpp
@@ -25,6 +25,16 @@
 #define DEBUG 0
 #include "debug.h"
 
+// FIXME: Define this only for SheepShaver. Kheperix will need
+// something like KPX_MAX_CPUS == 1.
+#ifndef SHEEPSHAVER
+#undef HAVE_STATIC_DATA_EXEC
+#endif
+
+#if HAVE_STATIC_DATA_EXEC
+static uint8 g_translation_cache[basic_jit_cache::JIT_CACHE_SIZE];
+#endif
+
 basic_jit_cache::basic_jit_cache(uint32 init_cache_size)
 	: tcode_start(NULL), code_start(NULL), code_p(NULL), code_end(NULL)
 {
@@ -41,8 +51,15 @@ basic_jit_cache::init_translation_cache(uint32 size)
 {
 	// Round up translation cache size to next 16 KB boundaries
 	const uint32 roundup = 16 * 1024;
-	cache_size = (size + JIT_CACHE_SIZE_GUARD + roundup - 1) & -roundup;
+	uint32 effective_cache_size = (size - JIT_CACHE_SIZE_GUARD) & -roundup;
+	cache_size = size & -roundup;
 
+#if HAVE_STATIC_DATA_EXEC
+	if (cache_size <= JIT_CACHE_SIZE) {
+		tcode_start = g_translation_cache;
+		goto done;
+	}
+#endif
 	tcode_start = (uint8 *)vm_acquire(cache_size, VM_MAP_PRIVATE | VM_MAP_32BIT);
 	if (tcode_start == VM_MAP_FAILED) {
 		tcode_start = NULL;
@@ -56,16 +73,21 @@ basic_jit_cache::init_translation_cache(uint32 size)
 		return false;
 	}
 	
+  done:
 	D(bug("basic_jit_cache: Translation cache: %d KB at %p\n", cache_size / 1024, tcode_start));
 	code_start = tcode_start;
 	code_p = code_start;
-	code_end = code_p + cache_size;
+	code_end = code_p + effective_cache_size;
 	return true;
 }
 
 void
 basic_jit_cache::kill_translation_cache()
 {
-	if (tcode_start)
+	if (tcode_start) {
+#if HAVE_STATIC_DATA_EXEC
+		if (cache_size > JIT_CACHE_SIZE)
+#endif
 		vm_release(tcode_start, cache_size);
+	}
 }
diff --git a/SheepShaver/src/kpx_cpu/src/cpu/jit/jit-cache.hpp b/SheepShaver/src/kpx_cpu/src/cpu/jit/jit-cache.hpp
index 92830214..0b734e78 100644
--- a/SheepShaver/src/kpx_cpu/src/cpu/jit/jit-cache.hpp
+++ b/SheepShaver/src/kpx_cpu/src/cpu/jit/jit-cache.hpp
@@ -28,8 +28,10 @@
 class basic_jit_cache
 {
 	// Default cache size (2 MB)
+public:
 	static const uint32 JIT_CACHE_SIZE = 2 * 1024 * 1024;
 	static const uint32 JIT_CACHE_SIZE_GUARD = 4096;
+private:
 	uint32 cache_size;
 
 	// Translation cache (allocated base, current pointer, end pointer)