demotool/ui-opemu.cc

#include "externals.hh"

#include "common.hh"
#include "c-sync.hh"

#include "ui.hh"
#include "ui-odbg.hh"
#include "ui-opemu.hh"
#include "ui-profiling.hh"
#include "ui-rendertarget.hh"

using namespace ops;
using namespace ebcl;


/*= EMULATOR ===================================================================*/

X_OpFailure::X_OpFailure(
		T_Op const& op ,
		T_String error ) noexcept
	: op_( &op ) , error_( std::move( error ) )
{
	T_StringBuilder sb;
	sb << "operation (" << op << ") failed: "
		<< error_ << "; source: " << op.location << '\0';
	fullMessage_ = std::move( sb );
}

char const* X_OpFailure::what( ) const noexcept
{
	return fullMessage_.data( );
}

/*------------------------------------------------------------------------------*/

T_OpContext::T_OpContext(
		T_OpProgram& program ) noexcept
	: program( program )
{
	stack.ensureCapacity( stack.growth( ) );

	const auto nc{ program.constants.size( ) };
	const auto ts{ 3 + nc + program.nVariables
		+ program.nFramebuffers + program.nPrograms
		+ program.nPipelines + program.nSamplers
		+ program.nTextures };
	values.resize( ts );
	initialInputs.resize( program.inputs.size( ) );

	framebuffers.resize( program.nFramebuffers );
	pipelines.resize( program.nPipelines );
	samplers.resize( program.nSamplers );
	textures.resize( program.nTextures );

	memset( &values[ 0 ] , 0 , values.size( ) * 4 );
	for ( auto i = 0u ; i < nc ; i ++ ) {
		values[ i + 3 + program.nVariables ] = program.constants[ i ];
	}
}

namespace {
struct T_RunGuard
{
	T_OpContext& context;
	T_RunGuard( T_OpContext& ctx ) noexcept : context( ctx ) {}

	~T_RunGuard( )
	{
		while ( !context.profiling.empty( ) ) {
			UI::Profiler( ).end( context.profiling.last( ) );
			context.profiling.removeLast( );
		}
		glUseProgram( 0 );
		glBindProgramPipeline( 0 );
		glBindFramebuffer( GL_FRAMEBUFFER , 0 );
		UI::Textures( ).reset( );
	}
};
}

void T_OpContext::run(
		const E_RunTarget target ,
		const float time ,
		const float width ,
		const float height )
{
	assert( !aborted );

	T_RunGuard rg( *this );
	x87sp = 0;
	instrPtr = program.ops.firstOf( target == R_INIT ? program.init : program.frame );
	values[ 0 ] = time;
	values[ 1 ] = width;
	values[ 2 ] = height;

	stack.clear( );
	stack.add( 0xffffffff );
	installOverrides.clear( );

	while ( !stack.empty( ) ) {
		auto const& instr{ program.ops[ instrPtr ] };

//#define YOUR_MUM_IS_A_TRACE
#ifdef YOUR_MUM_IS_A_TRACE
		GL_ASSERT( );
		T_StringBuilder sb;
		sb << "\nEXECUTE " << instrPtr << ":\t(" << instr << ") {"
			<< instr.location << "}\nSTACK:";
		for ( auto i = 0u ; i < stack.size( ) ; i ++ ) {
			sb << ' ' << stack[ i ].u;
		}
		sb << "\nFPU STACK:";
		for ( auto i = 0u ; i < x87sp ; i ++ ) {
			sb << ' ' << x87stack[ i ];
		}
		sb << "\nWREG: " << wreg.f << '/' << wreg.u << '\n' << '\0';
		printf( "%s" , sb.data( ) );

		printf( "VALUES\n00" );
		for ( auto i = 0u ; i < values.size( ) ; i ++ ) {
			printf( "    %08x" , values[ i ].u );
			if ( i % 4 == 3 ) {
				printf( "\n%02x" , i + 1 );
			}
		}
		if ( values.size( ) % 4 != 0 ) {
			printf( "\n" );
		}
#endif

		switch ( instr.op ) {

		    case OP_END:
			throw X_OpFailure{ instr , "invalid instruction" };

		    // --------------------------------------------------------------------------------

		    case OP_CALL:
			if ( program.ops.size( ) <= instr.args[ 0 ] ) {
				throw X_OpFailure{ instr , "invalid function index" };
			}
			stack.add( instrPtr + 1 );
			instrPtr = program.ops.firstOf( instr.args[ 0 ] );
			continue;

		    case OP_RET:
			ensureStack( instr , 1 + instr.args[ 0 ] );
			instrPtr = stack.last( ).u;
			stack.resize( stack.size( ) - instr.args[ 0 ] - 1 );
			continue;

		    case OP_SKIP:
			// FIXME: make sure we don't go past the end
			instrPtr += instr.args[ 0 ];
			break;

		    case OP_COND_SKIP:
			ensureStack( instr , 1 );
			if ( stack.last( ).u != instr.args[ 1 ] ) {
				// FIXME: make sure we don't go past the end
				instrPtr += instr.args[ 0 ];
			}
			break;

		    // --------------------------------------------------------------------------------

		    case OP_RES_STACK:
			stack.resize( stack.size( ) + instr.args[ 0 ] + 1 );
			break;

		    case OP_PUSH:
			stack.add( wreg );
			break;

		    case OP_POP:
			ensureStack( instr , instr.args[ 0 ] + 1 );
			stack.resize( stack.size( ) - instr.args[ 0 ] - 1 );
			break;

		    case OP_DUP:
			ensureStack( instr , instr.args[ 0 ] + 1 );
			stack.add( stack[ stack.size( ) - instr.args[ 0 ] - 1 ] );
			break;

		    // --------------------------------------------------------------------------------

		    case OP_LOAD:
			checkAddress( instr , instr.args[ 0 ] );
			wreg = values[ instr.args[ 0 ] ];
			break;

		    case OP_STORE:
			checkAddress( instr , instr.args[ 0 ] );
			values[ instr.args[ 0 ] ] = wreg;
			break;

		    case OP_SLOAD:
			ensureStack( instr , instr.args[ 0 ] + 1 );
			wreg = stack[ stack.size( ) - instr.args[ 0 ] - 1 ];
			break;

		    case OP_CONST:
		    case OP_OFFSET:
			wreg = instr.args[ 0 ];
			break;

		    // --------------------------------------------------------------------------------

		    case OP_GET_INPUT:
			ensureFpuStack( instr , 0 , 1 );
			x87stack[ x87sp ++ ] = Common::Sync( ).inputs( )[ instr.args[ 0 ] ];
			break;

		    case OP_FP_LOAD:
			ensureFpuStack( instr , 0 , 1 );
			checkAddress( instr , instr.args[ 0 ] );
			x87stack[ x87sp ++ ] = values[ instr.args[ 0 ] ].f;
			break;

		    case OP_FP_STORE:
			ensureFpuStack( instr , 1 , 0 );
			checkAddress( instr , instr.args[ 0 ] );
			values[ instr.args[ 0 ] ].f = x87stack[ -- x87sp ];
			break;

		    case OP_FP_SLOAD:
			ensureFpuStack( instr , 0 , 1 );
			ensureStack( instr , instr.args[ 0 ] + 1 );
			x87stack[ x87sp ++ ] = stack[ stack.size( ) - instr.args[ 0 ] - 1 ].f;
			break;

		    case OP_FP_SSTORE:
			ensureFpuStack( instr , 1 , 0 );
			ensureStack( instr , instr.args[ 0 ] + 1 );
			stack[ stack.size( ) - instr.args[ 0 ] - 1 ].f = x87stack[ -- x87sp ];
			break;

		    case OP_FP_SSTORE_INT:
			ensureFpuStack( instr , 1 , 0 );
			ensureStack( instr , instr.args[ 0 ] + 1 );
			stack[ stack.size( ) - instr.args[ 0 ] - 1 ].i = int32_t( x87stack[ -- x87sp ] );
			break;

		    // --------------------------------------------------------------------------------

		    case OP_FP_CMP:
		    {
			ensureFpuStack( instr , 2 , 0 );
			const auto v2( x87stack[ x87sp - 1 ] ) ,
					v1( x87stack[ x87sp - 2 ] );
			x87sp --;

			const bool rv{ ([&]( ) -> bool {
				switch ( instr.args[ 0 ] ) {
				    case 0: return v1 == v2;
				    case 1: return v1 != v2;
				    case 2: return v1 > v2;
				    case 3: return v1 >= v2;
				    case 4: return v1 < v2;
				    case 5: return v1 <= v2;
				}
				throw X_OpFailure( instr , "invalid operation" );
			})() };
			x87stack[ x87sp - 1 ] = rv ? 1 : 0;
			break;
		    }

		    case OP_FP_ADD:
		    {
			ensureFpuStack( instr , 2 , 0 );
			x87stack[ x87sp - 2 ] += x87stack[ x87sp - 1 ];
			x87sp --;
			break;
		    }

		    case OP_FP_SUB:
		    {
			ensureFpuStack( instr , 2 , 0 );
			x87stack[ x87sp - 2 ] -= x87stack[ x87sp - 1 ];
			x87sp --;
			break;
		    }

		    case OP_FP_MUL:
		    {
			ensureFpuStack( instr , 2 , 0 );
			x87stack[ x87sp - 2 ] *= x87stack[ x87sp - 1 ];
			x87sp --;
			break;
		    }

		    case OP_FP_DIV:
		    {
			ensureFpuStack( instr , 2 , 0 );
			if ( x87stack[ x87sp - 1 ] == 0 ) {
				throw X_OpFailure{ instr , "arithmetic error" };
			}
			x87stack[ x87sp - 2 ] /= x87stack[ x87sp - 1 ];
			x87sp --;
			break;
		    }

		    case OP_FP_POW:
		    {
			ensureFpuStack( instr , 2 , 0 );
			x87stack[ x87sp - 2 ] = pow( x87stack[ x87sp - 2 ] ,
					x87stack[ x87sp - 1 ] );
			x87sp --;
			break;
		    }

		    // --------------------------------------------------------------------------------

		    case OP_FP_NEG:
		    {
			ensureFpuStack( instr , 1 , 1 );
			x87stack[ x87sp - 1 ] = -x87stack[ x87sp - 1 ];
			break;
		    }

		    case OP_FP_INV:
		    {
			ensureFpuStack( instr , 1 , 1 );
			if ( x87stack[ x87sp - 1 ] == 0 ) {
				throw X_OpFailure{ instr , "arithmetic error" };
			}
			x87stack[ x87sp - 1 ] = 1.0 / x87stack[ x87sp - 1 ];
			break;
		    }

		    case OP_FP_NOT:
		    {
			ensureFpuStack( instr , 1 , 0 );
			x87stack[ x87sp - 1 ] = x87stack[ x87sp - 1 ] == 0 ? 1 : 0;
			break;
		    }

		    case OP_FP_SIN:
		    {
			ensureFpuStack( instr , 1 , 0 );
			x87stack[ x87sp - 1 ] = sin( x87stack[ x87sp - 1 ] );
			break;
		    }

		    case OP_FP_COS:
		    {
			ensureFpuStack( instr , 1 , 0 );
			x87stack[ x87sp - 1 ] = cos( x87stack[ x87sp - 1 ] );
			break;
		    }

		    case OP_FP_TAN:
		    {
			ensureFpuStack( instr , 1 , 1 );
			const auto c( cos( x87stack[ x87sp - 1 ] ) );
			if ( c == 0 ) {
				throw X_OpFailure{ instr , "arithmetic error" };
			}
			x87stack[ x87sp - 1 ] = sin( x87stack[ x87sp - 1 ] ) / c;
			break;
		    }

		    case OP_FP_SQRT:
		    {
			ensureFpuStack( instr , 1 , 0 );
			const auto v( x87stack[ x87sp - 1 ] );
			if ( v < 0 ) {
				throw X_OpFailure{ instr , "arithmetic error" };
			}
			x87stack[ x87sp - 1 ] = sqrt( v );
			break;
		    }

		    case OP_FP_EXP:
		    {
			ensureFpuStack( instr , 1 , 0 ); // FIXME: need FPU stack space
			x87stack[ x87sp - 1 ] = exp( x87stack[ x87sp - 1 ] );
			break;
		    }

		    case OP_FP_LN:
		    {
			ensureFpuStack( instr , 1 , 0 ); // FIXME: need FPU stack space
			x87stack[ x87sp - 1 ] = log( x87stack[ x87sp - 1 ] );
			break;
		    }

		    // --------------------------------------------------------------------------------

		    case OP_GEN_ASSETS:
		    {
			auto idx = 0u;
			switch ( instr.args[ 0 ] ) {
			    case 3: idx += program.nSamplers;
				    // fallthrough
			    case 2: idx += program.nPrograms + program.nPipelines;
				    // fallthrough
			    case 1: idx += program.nFramebuffers;
				    // fallthrough
			    case 0: idx += 3 + program.nVariables + program.constants.size( ); break;

			    default:
				throw X_OpFailure( instr , "invalid argument" );
			}

			auto count = 0u;
			switch ( instr.args[ 0 ] ) {
			    case 3: count = program.nTextures; break;
			    case 2: count = program.nSamplers; break;
			    case 1: count = program.nPipelines; break;
			    case 0: count = program.nFramebuffers; break;
			}


			for ( auto i = 0u ; i < count ; i ++ ) {
				values[ idx + i ].u = i + 1;
			}
			break;
		    }

		    case OP_INIT_PIPELINE:
		    {
			ensureStack( instr , 2 + instr.args[ 0 ] );

			const auto sv( stack.last( ).u );
			stack.removeLast( );
			if ( sv == 0  || sv > pipelines.size( ) ) {
				throw X_OpFailure{ instr , "invalid pipeline" };
			}
			const auto plIndex( sv - 1 );

			T_String progNames[ 6 ];
			for ( auto i = 0u ; i <= instr.args[ 0 ] ; i ++ ) {
				const auto prIndex( stack.last( ).u );
				stack.removeLast( );
				if ( !prIndex ) {
					throw X_OpFailure{ instr , "pipeline uses uninitialised program" };
				}
				progNames[ i ] = programs[ prIndex - 1 ]->name( );
			}

			pipelines[ plIndex ] = NewOwned< T_ShaderPipeline >(
					UI::Shaders( ).pipeline( progNames , instr.args[ 0 ] + 1 ) );
			break;
		    }

		    case OP_INIT_PROGRAM:
		    {
			if ( instr.args[ 0 ] >= program.progNames.size( ) ) {
				throw X_OpFailure{ instr , "invalid argument" };
			}
			programs.add( NewOwned< T_ShaderProgram >(
					UI::Shaders( ).program( program.progNames[ instr.args[ 0 ] ] ) ) );
			wreg = programs.size( );
			break;
		    }

		    case OP_INIT_SAMPLER:
		    {
			ensureStack( instr , 3 );
			const auto sv( stack.last( ).u );
			stack.removeLast( );
			if ( sv == 0 || sv > samplers.size( ) ) {
				throw X_OpFailure{ instr , "invalid sampler" };
			}

			const auto samplerIndex( sv - 1 );
			if ( !samplers[ samplerIndex ] ) {
				samplers[ samplerIndex ] = NewOwned< T_TextureSampler >( );
			}

			const float max( stack.last( ).f );
			stack.removeLast( );
			const float min( stack.last( ).f );
			stack.removeLast( );

			samplers[ samplerIndex ]->sampling( E_TexSampling( ( instr.args[ 0 ] & 4 ) >> 2 ) )
				.wrap( E_TexWrap( instr.args[ 1 ] ) )
				.lod( min , max );
			if ( ( instr.args[ 0 ] & 2 ) == 0 ) {
				samplers[ samplerIndex ]->noMipmap( );
			} else {
				samplers[ samplerIndex ]->mipmap( E_TexSampling( instr.args[ 0 ] & 1 ) );
			}

			break;
		    }

		    case OP_INIT_TEXTURE:
		    {
			ensureStack( instr , 3 + ( instr.args[ 1 ] ? 1 : 0 ) );

			const auto sv( stack.last( ).u );
			stack.removeLast( );
			if ( sv == 0 || sv > textures.size( ) ) {
				throw X_OpFailure{ instr , "invalid texture" };
			}

			const auto index( sv - 1 );
			const uint32_t w( stack.last( ).f );
			stack.removeLast( );
			const uint32_t h( stack.last( ).f );
			stack.removeLast( );
			const uint32_t lods( instr.args[ 1 ] ? stack.last( ).f : 1 );
			if ( instr.args[ 1 ] ) {
				stack.removeLast( );
			}

			textures[ index ] = NewOwned< T_Texture >(
					w , h , E_TexType( instr.args[ 0 ] ) , lods );
			break;
		    }

		    case OP_FB_ATTACH:
		    {
			// instr[ 0 ] = id (0 for depth attachment, 1+ for color attachments)
			// instr[ 1 ] = has LOD?
			// stack: TOP < TEX ( < LOD if has LOD )
			ensureStack( instr , 1 + ( instr.args[ 1 ] ? 1 : 0 ) );
			if ( curFb < 0 ) {
				throw X_OpFailure{ instr , "no framebuffer selected" };
			}

			const auto svt( stack.last( ).u );
			stack.removeLast( );
			if ( svt == 0 || svt > textures.size( ) || !textures[ svt - 1 ] ) {
				throw X_OpFailure{ instr , "invalid texture" };
			}
			const auto& texture( *textures[ svt - 1 ] );

			const uint32_t lod( instr.args[ 1 ] ? uint32_t( stack.last( ).f ) : 0 );
			if ( instr.args[ 1 ] ) {
				stack.removeLast( );
			}
			framebuffers[ curFb ]->attach( texture , lod , instr.args[ 0 ] );

			break;
		    }

		    // --------------------------------------------------------------------------------

		    case OP_USE_TEXTURE:
		    {
			ensureStack( instr , 2 );

			const auto svt( stack.last( ).u );
			stack.removeLast( );
			if ( svt == 0 || svt > textures.size( ) || !textures[ svt - 1 ] ) {
				throw X_OpFailure{ instr , "invalid texture" };
			}

			const auto svs( stack.last( ).u );
			stack.removeLast( );
			if ( svs == 0 || svs > samplers.size( ) || !samplers[ svs - 1 ] ) {
				throw X_OpFailure{ instr , "invalid sampler" };
			}

			UI::Textures( ).bind( instr.args[ 0 ] ,
					*textures[ svt - 1 ] , *samplers[ svs - 1 ] );
			break;
		    }

		    case OP_USE_PIPELINE:
		    {
			ensureStack( instr , 1 );

			const auto sv( stack.last( ).u );
			stack.removeLast( );
			if ( sv == 0 || sv > pipelines.size( ) || !pipelines[ sv - 1 ] ) {
				throw X_OpFailure{ instr , "invalid pipeline" };
			}
			pipelines[ sv - 1 ]->enable( );
			break;
		    }

		    case OP_USE_PROGRAM:
		    {
			ensureStack( instr , 1 );

			const auto sv( stack.last( ).u );
			stack.removeLast( );
			if ( sv == 0 || sv > programs.size( ) || !programs[ sv - 1 ] ) {
				throw X_OpFailure{ instr , "invalid program" };
			}
			programs[ sv - 1 ]->enable( );
			break;
		    }

		    case OP_FB_TOGGLE:
		    {
			if ( curFb < 0 ) {
				throw X_OpFailure{ instr , "no framebuffer selected" };
			}
			framebuffers[ curFb ]->toggle( instr.args[ 0 ] , instr.args[ 1 ] );
			break;
		    }

		    case OP_UNIFORMS:
		    {
			ensureStack( instr , 3 + instr.args[ 0 ] );

			const auto ss( stack.size( ) );
			T_OpValue values[ 4 ];
//			printf( "OP_UNIFORMS %d %d" , instr.args[ 0 ] , instr.args[ 1 ] );
			for ( auto i = 0u ; i <= instr.args[ 0 ] ; i ++ ) {
				if ( instr.args[ 1 ] ) {
					values[ i ] = uint32_t( stack[ ss - 3 - i ].f );
//					printf( " %d" , values[ i ].i );
				} else {
					values[ i ] = stack[ ss - 3 - i ];
//					printf( " %f" , values[ i ].f );
				}
			}

			const auto sv( stack.last( ).u );
			if ( sv == 0 || sv > programs.size( ) || !programs[ sv - 1 ] ) {
				throw X_OpFailure{ instr , "invalid program" };
			}
//			printf( " -> %s %d\n" , programs[ sv - 1 ]->name( ).toOSString( ).data( ) , stack[ ss - 2 ].u );

			typedef void (*F_SetUniform_)( int , int , int , void* );
			void const* const funcs[] = {
				&glProgramUniform1fv , &glProgramUniform2fv , &glProgramUniform3fv , &glProgramUniform4fv ,
				&glProgramUniform1iv , &glProgramUniform2iv , &glProgramUniform3iv , &glProgramUniform4iv ,
			};
			const F_SetUniform_ func{ *(F_SetUniform_*) funcs[
				instr.args[ 0 ] + ( instr.args[ 1 ] ? 4 : 0 ) ] };
			func( programs[ sv - 1 ]->id( ) , stack[ ss - 2 ].u , 1 , values );
			stack.resize( ss - 3 - instr.args[ 0 ] );
			break;
		    }

		    case OP_VIEWPORT:
		    {
			ensureStack( instr , 4 );
			const auto ss( stack.size( ) );
			glViewport( int32_t( stack[ ss - 1 ].f ) ,
					int32_t( stack[ ss - 2 ].f ) ,
					int32_t( stack[ ss - 3 ].f ) ,
					int32_t( stack[ ss - 4 ].f ) );
			stack.resize( ss - 4 );
			break;
		    }

		    case OP_USE_FRAMEBUFFER:
		    {
			ensureStack( instr , 1 );
			const auto sv( stack.last( ).u );
			stack.removeLast( );
			if ( sv == 0 ) {
				glBindFramebuffer( GL_FRAMEBUFFER , 0 );
				curFb = -1;
				break;
			}

			const auto index( sv - 1 );
			if ( !framebuffers[ index ] ) {
				framebuffers[ index ] = NewOwned< T_Rendertarget >( );
			}
			glBindFramebuffer( GL_FRAMEBUFFER , framebuffers[ index ]->id( ) );
			curFb = index;
			break;
		    }

		    // --------------------------------------------------------------------------------

		    case OP_FULLSCREEN:
			glDrawArrays( GL_TRIANGLE_STRIP , 0 , 4 );
			break;

		    case OP_CLEAR:
		    {
			ensureStack( instr , 4 );
			const auto ss( stack.size( ) );
			glClearColor( stack[ ss - 1 ].f , stack[ ss - 2 ].f ,
					stack[ ss - 3 ].f , stack[ ss - 4 ].f );
			glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
			stack.resize( ss - 4 );
			break;
		    }

		    // --------------------------------------------------------------------------------

		    case OP_UI_PENTER:
		    {
			T_String const& section( program.uiStrings[ instr.args[ 0 ] ] );
			UI::Profiler( ).start( section );
			profiling.add( section );
			break;
		    }

		    case OP_UI_PEXIT:
		    	glFinish( );
			UI::Profiler( ).end( profiling.last( ) );
			profiling.removeLast( );
			break;

		    case OP_UI_INPUT_DFT:
			initialInputs[ instr.args[ 0 ] ] = values[ instr.args[ 1 ] ].f;
			break;

		    case OP_UI_INPUT_OVR:
			if ( !installOverrides ) {
				installOverrides = NewOwned< T_SyncOverrideSection >( "*" );
			}
			installOverrides->merge( *( program.overrides[ instr.args[ 0 ] ] ) );
			break;

		    case OP_UI_ODBG:
		    {
			ensureStack( instr , 1 );
			const auto svt( stack.last( ).u );
			stack.removeLast( );
			if ( svt == 0 || svt > textures.size( ) || !textures[ svt - 1 ] ) {
				throw X_OpFailure{ instr , "invalid texture" };
			}
			UI::ODbg( ).registerTexture( *textures[ svt - 1 ] ,
					E_ODbgMode( instr.args[ 0 ] ) ,
					program.uiStrings[ instr.args[ 1 ] ] );
			break;
		    }
		}

		instrPtr ++;
	}
}

void T_OpContext::ensureStack(
		T_Op const& op ,
		const uint32_t min )
{
	if ( stack.size( ) < min ) {
		throw X_OpFailure{ op , "stack underrun" };
	}
}

void T_OpContext::ensureFpuStack(
		T_Op const& op ,
		const uint32_t minStacked ,
		const uint32_t minFree )
{
	if ( x87sp < minStacked ) {
		throw X_OpFailure{ op , "FPU stack underrun" };
	}
	if ( 8 - x87sp < minFree ) {
		throw X_OpFailure{ op , "FPU stack overflow" };
	}
}

void T_OpContext::checkAddress(
		T_Op const& op ,
		const uint32_t address )
{
	if ( address >= values.size( ) ) {
		throw X_OpFailure( op , "invalid access" );
	}
}