Unexpected resets on mbed platform

I have a custom design based on the LPC11U37. It will run for a period and then resets. I am puzzled what is causing this to occur. I am running with the the IRC clock, my reset pin is connected to nothing but a pushbutton switch, and the code enters an infinite loop once initialization is complete. There are no interrupts.

The code for this project has been compiled under two different mbed targets, an LPC11U24 and an LPC11U35. It would be really nice if the mbed project would support the chip I am using also, but that does not seem to be the case currently.

What might cause the device to leave this loop and start over?