Assembly Lecture5

Lecture 5 and Lecture 6Chapter 7 Program Logic and ControlChapter OutlineShort, near and far addressJMP Instructionhe CMP InstructionConditional Jump instructionhe Loop instruction!hile Loop"#P#$ LoopShort,near,and far addresses1- A short address, limited to a distance of -128 to 127 bytes2- A near address, limited to a distance of -32,768 to 32,767 bytes3- A far address, which may be within the same segment at a distance over 32K or in other segmentSHORT NEAR FARJMP YES YES YESJXXX(conditional jump) YES YES NOLOOP YES NO NOCALL NlA YES YES%nconditional Jumps & he JMP Instruction he JMP !"#m$% instr#ction ca#ses an #nconditional transfer of control !#nconditional "#m$%& 'ynta() *+, destination-(am$le *+,.1/00&&.1/)12334JMP SHORT/NEAR/FAR address%nconditional Jumps & he JMP Instruction'ac()ard and *or)ard +umps5ac6ward)

.1/) 00&*+, .1/7orward) *+, .1/00&.1/)

he CMP Instruction he "#m$ condition is often $rovided by the CMP !com$are% instr#ction 'ynta() 3+, destination, so#rce 3om$ares by com$#ting destination contents min#s so#rce contents& he res#lt is not stored, b#t the flags are affected& 8estination may not be a constant& 3+, is "#st li6e '95, e(ce$t that destination is not changed&Conditional Jumps'ynta( *((( destination:label -(am$le *2;,