Is float point permited in interrups ? Were I can find recomendations on float point in interrupts for RV compiler and lpc21xx target ?
But what about
__irq Enables a C or C++ function to be used as an interrupt routine called by the IRQ or FIQ vectors. All corrupted registers except floating-point registers are preserved, not only those that are normally preserved under the AAPCS. The default AAPCS mode must be used.