Implement Cyrix EMMI extensions and 4 FPU instructions

PADDSIW, PSUBSIW, PMULHRW (named PMULHRWC in the code as recognized by some assemblers), PMULHRIW, PDISTIB, PMACHRIW, PAVEB, PMAGW, PMVZB, PMVNZB, PMVLZB, PMVGEZB, FTSTP, FRINT2, FRINEAR, FRICHOP are implemented for Cyrix 6x86MX. Cyrix 6x86(L) only has the last 4 instructions.

src/cpu/x86.c

@@ -272,6 +272,10 @@ reset_common(int hard)
     msr.fcr        = (1 << 8) | (1 << 9) | (1 << 12) | (1 << 16) | (1 << 19) | (1 << 21);
     msw            = 0;
     new_ne         = 0;
+
+    ccr0 = ccr1 = ccr2 = ccr3 = ccr4 = ccr5 = ccr6 = ccr7 = 0;
+    ccr4 = 0x85;
+
     if (hascache)
         cr0 = 1 << 30;
     else