Add imm_xchg_w and xchg_w commands, change XXXrev to xchg_XXX, tidy up slightly
-rw-r--r-- 74 .gitignore
-rw-r--r-- 57 Makefile
-rwxr-xr-x 331 asxxxx_build.sh
-rw-r--r-- 14666 cordic.c
-rw-r--r-- 1342 div.c
-rwxr-xr-x 181 n.sh
-rwxr-xr-x 187 o.sh
-rw-r--r-- 17203 sm.asm
-rw-r--r-- 16731 sm2.asm