APPENDIX C SUPPORT FOR FLOATING-POINT OPERATION COPROCESSOR
The RI850V4 manipulates the floating-point configuration/status register (FPSR) for floating-point operation. The user can change the floating-point operation settings from processing programs as needed by changing this register value.
The value of FPSR is essentially specified independently for each processing program and is not inherited between processing programs.
However, the RI850V4 does not manipulate FPSR when an extended service call routine starts or ends. For this reason, an extended service call routine inherits the FPSR value from the previous processing executed before the extended service call routine, and the value changed in a processing program is retained after the program ends.