There's no way to write floating points to a file from the floating point registers st0 <> st7
For example:
; st(0) = 0.0 ; Direct evalling eval "st0: {st(0)}" log $RESULT ; Logs: "st0: {st(0)}" ; Temporary storing the value mov flt, st(0) ; flt: 0.0 eval "st0: {flt}" log $RESULT ; Logs: "st0: {flt}" ; Without text in front log st(0) ; Works fine... wrt "test.txt", st(0) ; 'error'