Online HelpPC 2.10      Quick Reference Utility     Copyright 1991 David Jurgens
 
                     CPU Characteristics / Determination                     
                                                                                         8088,80188,V20  six byte prefetch queue, allows use of self                                      modifying code to determine length of prefetch                                                                                                    8086,80186,V30  four byte prefetch queue, allows use of self                                     modifying code to determine length of prefetch                                                                                                    8088,8086,80188,81086,v20,v30   Flag register bits 12 through                                    15 cannot be cleared                                                                                                                              8088,8086       will shift left or right using all 8 bits of                                     CL, if CL = 33, register is guaranteed to be                                     cleared                                                                                                                                           80188,80186,80286,80386 will shift left or right using only                                      lower 5 bits of CL.  If CL = 32, the shift will                                  not occur                                                                                                                                         80286,80386     earlier CPU's decremented SP before a PUSH SP, but                               286+ pushes the value first then, decrements SP                                                                                                   8088,8086       non-zero multiplication result clears zero flag                                                                                                   V20,V30         non-zero multiplication result does not clear                                    zero flag, set ZF before multiply, and test after,                               if it's still set, then it's a V20, V30                                                                                                            80286          allows setting of bit 15 of the flags register                                                                                                     80386          allows setting of bits 12 through 14 of flags register                                                                                                                                                                             see BIBLIO reference to  PC Tech Journal, "Chips In Transition",                 April 1986                                                                                                                                                                                                                                  
[helppc.bosbyte.nl]                   CPU                     Home  Back  Topics