Phyton produces professional, cost-effective development tools for ARM, Cortex, 8051 and other 8- to 32-bit embedded microcontrollers. The tools include IDEs (Integrated Development Environments), C compilers, software simulators, JTAG, on-chip, and in-circuit emulators, tracers, and evaluation boards...
CodeMaster™-ARM is an easy-to-use IDE that includes everything that is needed for developing applications that use ARM7, ARM9 and Cortex-M microcontrollers. The toolset is based on the Phyton original, highly optimized Phyton CMC compiler.
Phyton in-circuit and on-chip emulators for 8051 devices offer the widest device support in the industry, integration with best C compilers and all standard and high end features. 

Link: http://www.phyton.com