floatx.asm: add specific tests for exponent boundary conditions
floatx.asm: add specific tests for exponent boundary conditions

Add tests for the exponent boundaries (underflow, denorm, normal).

turingstudio/nasm,projedi/nasm,Distrotech/nasm,Distrotech/nasm,techkey/nasm,techkey/nasm,letolabs/nasm,projedi/nasm,techkey/nasm,turingstudio/nasm,turingstudio/nasm,turingstudio/nasm,techkey/nasm,Distrotech/nasm,letolabs/nasm,projedi/nasm,techkey/nasm,projedi/nasm,projedi/nasm,letolabs/nasm,Distrotech/nasm