eval.c: replace sequence of ifs with switch
eval.c: replace sequence of ifs with switch

Replace a sequence of "if" statements with a switch.

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