diff --git a/tools/emulator/opengl/host/tools/emugen/ApiGen.cpp b/tools/emulator/opengl/host/tools/emugen/ApiGen.cpp
index 9818e5db4..3df3107a9 100644
--- a/tools/emulator/opengl/host/tools/emugen/ApiGen.cpp
+++ b/tools/emulator/opengl/host/tools/emugen/ApiGen.cpp
@@ -165,6 +165,12 @@ int ApiGen::genContext(const std::string & filename, SideType side)
     // init function
     fprintf(fp, "\tint initDispatchByName( void *(*getProc)(const char *name, void *userData), void *userData);\n");
 
+    //client site set error virtual func
+    if (side == CLIENT_SIDE) {
+        fprintf(fp, "\tvirtual void setError(unsigned int  error){};\n");
+        fprintf(fp, "\tvirtual unsigned int getError(){ return 0; };\n");
+    }
+
     fprintf(fp, "};\n");
 
     fprintf(fp, "\n#endif\n");
@@ -222,6 +228,13 @@ int ApiGen::genEntryPoints(const std::string & filename, SideType side)
 
         bool shouldReturn = !e->retval().isVoid();
         bool shouldCallWithContext = (side == CLIENT_SIDE);
+        //param check
+        if (shouldCallWithContext) {
+            for (size_t j=0; j<e->vars().size(); j++) {
+                if (e->vars()[j].paramCheckExpression() != "") 
+                    fprintf(fp, "\t%s\n", e->vars()[j].paramCheckExpression().c_str());
+            }
+        }
         fprintf(fp, "\t %sctx->%s(%s",
                 shouldReturn ? "return " : "",
                 e->name().c_str(),
diff --git a/tools/emulator/opengl/host/tools/emugen/EntryPoint.cpp b/tools/emulator/opengl/host/tools/emugen/EntryPoint.cpp
index 03410272e..413b56af6 100644
--- a/tools/emulator/opengl/host/tools/emugen/EntryPoint.cpp
+++ b/tools/emulator/opengl/host/tools/emugen/EntryPoint.cpp
@@ -225,6 +225,24 @@ int EntryPoint::setAttribute(const std::string &line, size_t lc)
         // set the size expression into var
         pos = last;
         v->setLenExpression(line.substr(pos));
+    } else if (token == "param_check") {
+        pos = last;
+        std::string varname = getNextToken(line, pos, &last, WHITESPACE);
+
+        if (varname.size() == 0) {
+            fprintf(stderr, "ERROR: %u: Missing variable name in 'param_check' attribute\n", (unsigned int)lc);
+            return -1;
+        }
+        Var * v = var(varname);
+        if (v == NULL) {
+            fprintf(stderr, "ERROR: %u: variable %s is not a parameter of %s\n",
+                    (unsigned int)lc, varname.c_str(), name().c_str());
+            return -2;
+        }
+        // set the size expression into var
+        pos = last;
+        v->setParamCheckExpression(line.substr(pos));
+
     } else if (token == "dir") {
         pos = last;
         std::string varname = getNextToken(line, pos, &last, WHITESPACE);
diff --git a/tools/emulator/opengl/host/tools/emugen/Var.h b/tools/emulator/opengl/host/tools/emugen/Var.h
index ba74cea48..c9735c714 100644
--- a/tools/emulator/opengl/host/tools/emugen/Var.h
+++ b/tools/emulator/opengl/host/tools/emugen/Var.h
@@ -30,7 +30,8 @@ public:
         m_lenExpression(""),
         m_pointerDir(POINTER_IN),
         m_nullAllowed(false),
-        m_packExpression("")
+        m_packExpression(""),
+        m_paramCheckExpression("")
 
     {
     }
@@ -45,7 +46,8 @@ public:
         m_lenExpression(lenExpression),
         m_pointerDir(dir),
         m_nullAllowed(false),
-        m_packExpression(packExpression)
+        m_packExpression(packExpression),
+		m_paramCheckExpression("")	
     {
     }
 
@@ -67,8 +69,10 @@ public:
     bool isVoid() const { return ((m_type->bytes() == 0) && (!m_type->isPointer())); }
     const std::string & lenExpression() const { return m_lenExpression; }
     const std::string & packExpression() const { return(m_packExpression); }
+    const std::string & paramCheckExpression() const { return m_paramCheckExpression; }
     void setLenExpression(const std::string & lenExpression) { m_lenExpression = lenExpression; }
     void setPackExpression(const std::string & packExpression) { m_packExpression = packExpression; }
+    void setParamCheckExpression(const std::string & paramCheckExpression) { m_paramCheckExpression = paramCheckExpression; }
     void setPointerDir(PointerDir dir) { m_pointerDir = dir; }
     PointerDir pointerDir() { return m_pointerDir; }
     void setNullAllowed(bool state) { m_nullAllowed = state; }
@@ -84,6 +88,7 @@ private:
     PointerDir m_pointerDir;
     bool m_nullAllowed;
     std::string m_packExpression; // an expression to pack data into the stream
+    std::string m_paramCheckExpression; //an expression to check parameter value
 
 };
 
diff --git a/tools/emulator/opengl/shared/OpenglCodecCommon/gl_base_types.h b/tools/emulator/opengl/shared/OpenglCodecCommon/gl_base_types.h
index 8a7ad58f0..d7bdef8bf 100644
--- a/tools/emulator/opengl/shared/OpenglCodecCommon/gl_base_types.h
+++ b/tools/emulator/opengl/shared/OpenglCodecCommon/gl_base_types.h
@@ -48,4 +48,15 @@ typedef char *GLstr;
 /* JR XXX Treating this as an in handle - is this correct? */
 typedef void * GLeglImageOES;
 
+/* ErrorCode */
+#ifndef GL_INVALID_ENUM
+#define GL_NO_ERROR                       0
+#define GL_INVALID_ENUM                   0x0500
+#define GL_INVALID_VALUE                  0x0501
+#define GL_INVALID_OPERATION              0x0502
+#define GL_STACK_OVERFLOW                 0x0503
+#define GL_STACK_UNDERFLOW                0x0504
+#define GL_OUT_OF_MEMORY                  0x0505
+#endif
+
 #endif
diff --git a/tools/emulator/opengl/system/GLESv1_enc/GLEncoder.cpp b/tools/emulator/opengl/system/GLESv1_enc/GLEncoder.cpp
index ef1e4b8fe..653f71f1d 100644
--- a/tools/emulator/opengl/system/GLESv1_enc/GLEncoder.cpp
+++ b/tools/emulator/opengl/system/GLESv1_enc/GLEncoder.cpp
@@ -36,6 +36,18 @@ static GLubyte *gExtensionsString= (GLubyte *) ""; // no extensions at this poin
         return ret; \
     }
 
+GLenum GLEncoder::s_glGetError(void * self)
+{
+    GLEncoder *ctx = (GLEncoder *)self;
+    GLenum err = ctx->getError();
+    if(err != GL_NO_ERROR) {
+        ctx->setError(GL_NO_ERROR);
+        return err;
+    }
+
+    return ctx->m_glGetError_enc(self);
+
+}
 
 GLint * GLEncoder::getCompressedTextureFormats()
 {
@@ -453,6 +465,7 @@ GLEncoder::GLEncoder(IOStream *stream) : gl_encoder_context_t(stream)
 {
     m_initialized = false;
     m_state = NULL;
+    m_error = GL_NO_ERROR;
     m_num_compressedTextureFormats = 0;
     m_compressedTextureFormats = NULL;
     // overrides;
@@ -481,6 +494,7 @@ GLEncoder::GLEncoder(IOStream *stream) : gl_encoder_context_t(stream)
     m_glDrawElements_enc = set_glDrawElements(s_glDrawElements);
     set_glGetString(s_glGetString);
     set_glFinish(s_glFinish);
+    m_glGetError_enc = set_glGetError(s_glGetError);
 
 }
 
diff --git a/tools/emulator/opengl/system/GLESv1_enc/GLEncoder.h b/tools/emulator/opengl/system/GLESv1_enc/GLEncoder.h
index 6275820dc..7471bfb38 100644
--- a/tools/emulator/opengl/system/GLESv1_enc/GLEncoder.h
+++ b/tools/emulator/opengl/system/GLESv1_enc/GLEncoder.h
@@ -34,16 +34,21 @@ public:
     void setInitialized(){ m_initialized = true; };
     bool isInitialized(){ return m_initialized; };
 
+    virtual void setError(GLenum error){ m_error = error; };
+    virtual GLenum getError() { return m_error; };
+
 private:
 
     bool    m_initialized;
     GLClientState *m_state;
+    GLenum  m_error;
     FixedBuffer m_fixedBuffer;
     GLint *m_compressedTextureFormats;
     GLint m_num_compressedTextureFormats;
 
     GLint *getCompressedTextureFormats();
     // original functions;
+    glGetError_client_proc_t    m_glGetError_enc;
     glGetIntegerv_client_proc_t m_glGetIntegerv_enc;
     glGetFloatv_client_proc_t m_glGetFloatv_enc;
     glGetFixedv_client_proc_t m_glGetFixedv_enc;
@@ -69,6 +74,7 @@ private:
     glFlush_client_proc_t m_glFlush_enc;
 
     // statics
+    static GLenum s_glGetError(void * self);
     static void s_glGetIntegerv(void *self, GLenum pname, GLint *ptr);
     static void s_glGetBooleanv(void *self, GLenum pname, GLboolean *ptr);
     static void s_glGetFloatv(void *self, GLenum pname, GLfloat *ptr);
diff --git a/tools/emulator/opengl/system/GLESv1_enc/gl.attrib b/tools/emulator/opengl/system/GLESv1_enc/gl.attrib
index d3d97fcc2..8c0308460 100644
--- a/tools/emulator/opengl/system/GLESv1_enc/gl.attrib
+++ b/tools/emulator/opengl/system/GLESv1_enc/gl.attrib
@@ -99,10 +99,12 @@ glCompressedTexSubImage2D
 #void glDeleteBuffers(GLsizei n, GLuint *buffers)
 glDeleteBuffers
 	len buffers (n * sizeof(GLuint))
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glDeleteTextures(GLsizei n, GLuint *textures)
 glDeleteTextures
 	len textures (n * sizeof(GLuint))
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #this function is marked as unsupported - it shouldn't be called directly
 #instead it translated into - glDrawDirectElements and glDrawIndirectElements
@@ -129,11 +131,13 @@ glGetBufferParameteriv
 glGenBuffers
 	len buffers (n * sizeof(GLuint))
 	dir buffers out
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glGenTextures(GLsizei n, GLuint *textures)
 glGenTextures
 	len textures (n * sizeof(GLuint))
 	dir textures out
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glGetFixedv(GLenum pname, GLfixed *params)
 glGetFixedv
@@ -465,11 +469,13 @@ glTexParameterxvOES
 glDeleteRenderbuffersOES
 	dir renderbuffers in
 	len renderbuffers (n * sizeof(GLuint))
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glGenRenderbuffersOES(GLsizei n, GLuint *renderbuffers)
 glGenRenderbuffersOES
 	dir renderbuffers in
 	len renderbuffers (n * sizeof(GLuint))
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glGetRenderbufferParameterivOES(GLenum target, GLenum pname, GLint *params)
 glGetRenderbufferParameterivOES
@@ -480,11 +486,13 @@ glGetRenderbufferParameterivOES
 glDeleteFramebuffersOES
 	dir framebuffers in
 	len framebuffers (n * sizeof(GLuint))
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glGenFramebuffersOES(GLsizei n, GLuint *framebuffers)
 glGenFramebuffersOES
 	dir framebuffers out
 	len framebuffers (n * sizeof(GLuint))
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glGetFramebufferAttachmentParameterivOES(GLenum target, GLenum attachment, GLenum pname, GLint *params)
 glGetFramebufferAttachmentParameterivOES
@@ -559,11 +567,13 @@ glGetTexGenxvOES
 glDeleteVertexArraysOES
 	dir arrays in
 	len arrays (n * sizeof(GLuint))
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glGenVertexArraysOES(GLsizei n, GLuint *arrays)
 glGenVertexArraysOES
 	dir arrays out
 	len arrays (n * sizeof(GLuint))
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glDiscardFramebufferEXT(GLenum target, GLsizei numAttachments, const GLenum *attachments)
 glDiscardFramebufferEXT
@@ -590,11 +600,13 @@ glMultiDrawElementsSUN
 glDeleteFencesNV
 	dir fences in
 	len fences (n * sizeof(GLuint))
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glGenFencesNV(GLsizei n, GLuint *fences)
 glGenFencesNV
 	dir fences in
 	len fences (n * sizeof(GLuint))
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glGetFenceivNV(GLuint fence, GLenum pname, GLint *params)
 glGetFenceivNV
diff --git a/tools/emulator/opengl/system/GLESv2_enc/GL2Encoder.cpp b/tools/emulator/opengl/system/GLESv2_enc/GL2Encoder.cpp
index 1d645914e..969c0c981 100644
--- a/tools/emulator/opengl/system/GLESv2_enc/GL2Encoder.cpp
+++ b/tools/emulator/opengl/system/GLESv2_enc/GL2Encoder.cpp
@@ -11,6 +11,7 @@ GL2Encoder::GL2Encoder(IOStream *stream) : gl2_encoder_context_t(stream)
 {
     m_initialized = false;
     m_state = NULL;
+    m_error = GL_NO_ERROR;
     m_num_compressedTextureFormats = 0;
     m_compressedTextureFormats = NULL;
     //overrides
@@ -31,6 +32,7 @@ GL2Encoder::GL2Encoder(IOStream *stream) : gl2_encoder_context_t(stream)
     m_glGetVertexAttribPointerv = set_glGetVertexAttribPointerv(s_glGetVertexAttribPointerv);
     set_glShaderSource(s_glShaderSource);
     set_glFinish(s_glFinish);
+    m_glGetError_enc = set_glGetError(s_glGetError);
 }
 
 GL2Encoder::~GL2Encoder()
@@ -38,6 +40,19 @@ GL2Encoder::~GL2Encoder()
     delete m_compressedTextureFormats;
 }
 
+GLenum GL2Encoder::s_glGetError(void * self)
+{
+    GL2Encoder *ctx = (GL2Encoder *)self;
+    GLenum err = ctx->getError();
+    if(err != GL_NO_ERROR) {
+        ctx->setError(GL_NO_ERROR);
+        return err;
+    }
+
+    return ctx->m_glGetError_enc(self);
+
+}
+
 void GL2Encoder::s_glFlush(void *self)
 {
     GL2Encoder *ctx = (GL2Encoder *) self;
diff --git a/tools/emulator/opengl/system/GLESv2_enc/GL2Encoder.h b/tools/emulator/opengl/system/GLESv2_enc/GL2Encoder.h
index 3365d0603..bbe5659a7 100644
--- a/tools/emulator/opengl/system/GLESv2_enc/GL2Encoder.h
+++ b/tools/emulator/opengl/system/GLESv2_enc/GL2Encoder.h
@@ -37,10 +37,14 @@ public:
     void setInitialized(){ m_initialized = true; };
     bool isInitialized(){ return m_initialized; };
 
+    virtual void setError(GLenum error){ m_error = error; };
+    virtual GLenum getError() { return m_error; };
+
 private:
 
     bool    m_initialized;
     GLClientState *m_state;
+    GLenum  m_error;
 
     GLint *m_compressedTextureFormats;
     GLint m_num_compressedTextureFormats;
@@ -50,6 +54,9 @@ private:
 
     void sendVertexAttributes(GLint first, GLsizei count);
 
+    glGetError_client_proc_t    m_glGetError_enc;
+    static GLenum s_glGetError(void * self);
+
     glFlush_client_proc_t m_glFlush_enc;
     static void s_glFlush(void * self);
 
diff --git a/tools/emulator/opengl/system/GLESv2_enc/gl2.attrib b/tools/emulator/opengl/system/GLESv2_enc/gl2.attrib
index 118fe5841..3b37bd898 100644
--- a/tools/emulator/opengl/system/GLESv2_enc/gl2.attrib
+++ b/tools/emulator/opengl/system/GLESv2_enc/gl2.attrib
@@ -26,18 +26,22 @@ glCompressedTexSubImage2D
 #void glDeleteBuffers(GLsizei n, GLuint *buffers)
 glDeleteBuffers
 	len buffers (n * sizeof(GLuint))
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glDeleteFramebuffers(GLsizei n, GLuint *framebuffers)
 glDeleteFramebuffers
 	len framebuffers (n * sizeof(GLuint))
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glDeleteRenderbuffers(GLsizei n, GLuint *renderbuffers)
 glDeleteRenderbuffers
 	len renderbuffers (n * sizeof(GLuint))
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glDeleteTextures(GLsizei n, GLuint *textures)
 glDeleteTextures
 	len textures (n * sizeof(GLuint))
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glDrawElements(GLenum mode, GLsizei count, GLenum type, GLvoid *indices)
 glDrawElements
@@ -47,21 +51,25 @@ glDrawElements
 glGenBuffers
 	len buffers (n * sizeof(GLuint))
 	dir buffers out
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glGenFramebuffers(GLsizei n, GLuint *framebuffers)
 glGenFramebuffers
 	len framebuffers (n * sizeof(GLuint))
 	dir framebuffers out
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glGenRenderbuffers(GLsizei n, GLuint *renderbuffers)
 glGenRenderbuffers
 	len renderbuffers (n * sizeof(GLuint))
 	dir renderbuffers out
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glGenTextures(GLsizei n, GLuint *textures)
 glGenTextures
 	len textures (n * sizeof(GLuint))
 	dir textures out
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glGetActiveAttrib(GLuint program, GLuint index, GLsizei bufsize, GLsizei *length, GLint *size, GLenum *type, GLchar *name)
 glGetActiveAttrib
@@ -330,11 +338,13 @@ glCompressedTexSubImage3DOES
 #void glDeleteVertexArraysOES(GLsizei n, GLuint *arrays)
 glDeleteVertexArraysOES
 	len arrays (n * sizeof(GLuint))
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 #void glGenVertexArraysOES(GLsizei n, GLuint *arrays)
 glGenVertexArraysOES
 	len arrays (n * sizeof(GLuint))
 	dir arrays out
+    param_check n if(n<0){ ctx->setError(GL_INVALID_VALUE); return; } 
 
 
 #void glDiscardFramebufferEXT(GLenum target, GLsizei numAttachments, GLenum *attachments)