IAR Embedded Workbench for 8051

AR Embedded Workbench is a set of development tools for building and debugging embedded system applications using assembler, C and C . It provides a completely integrated development environment that includes a project manager, editor, build tools and the C-SPY debugger.
IAR C/C Compiler is well known for its efficient code generation; each compiler contains both generic global optimizations as well as low-level chip-specific optimizations that ensure a small code size while taking advantage of all the specific features of your selected device.