pos机提示标志（pos机信号显示x）
???ÿ???ʾ??????? ?и?S??־??ʲô??˼???????ı??ֱ?ʶ???? ????ҵĻ??ҷ??ţ?NT\( ??̨?ҵĻ??ҷ??ţ? ? ??Ԫ/????Ԫ?Ļ??ҷ??? ???? Ӣ?? ??? ŷԪ?ķ??ţ? ? ̩?????ţ? \) ??Ԫ
????8088⁄8086??־?Ĵ????б?־??????,ͨ??ʾ??˵????????ñ?־λ??ֵ?Լ????ñꣿ????????־λ
1????λ??־CF(Carry Flag)
??λ??־CF??Ҫ??????ӳ?????Ƿ??????λ???λ????????????????λ??????һ????λ???λ????ô????ֵΪ1????????ֵΪ0??
ʹ?øñ?־λ??????У?????(?ֽ?)???ļӼ????㣬???????Ĵ?С?Ƚ????㣬??λ????????(?ֽ?)֮????λ??ר?Ÿı?CFֵ??ָ??ȡ?
2????ż??־PF(Parity Flag)
??ż??־PF???ڷ?ӳ???????С?1???ĸ???????ż?ԡ??????1???ĸ???Ϊż??????PF??ֵΪ1????????ֵΪ0??
????PF?ɽ?????żУ???飬???????żУ??λ???????ݴ??????У?Ϊ???ṩ???͵Ŀɿ??ԣ??????????żУ??ķ??????Ϳ?ʹ?øñ?־λ??
3????????λ??־AF(Auxiliary Carry Flag)
?ڷ??????????ʱ????????λ??־AF??ֵ????Ϊ1????????ֵΪ0??
(1)?????ֲ???ʱ?????????ֽ?????ֽڽ?λ???λʱ??
(2)?????ֽڲ???ʱ????????4λ???4λ??λ???λʱ??
??????6??????????־λ????һ????????£???־λCF??ZF??SF??OF??ʹ??Ƶ?ʽϸߣ?????־λPF??AF??ʹ??Ƶ?ʽϵ͡?
4?????־ZF(Zero Flag)
???־ZF??????ӳ???????Ƿ?Ϊ0???????????Ϊ0??????ֵΪ1????????ֵΪ0?????ж????????Ƿ?Ϊ0ʱ????ʹ?ô˱?־λ??
5?????ű?־SF(Sign Flag)
???ű?־SF??????ӳ???????ķ???λ?????????????????λ??ͬ??????ϵͳ?У??з????????ò????ʾ???????ԣ?SFҲ?ͷ?ӳ?????????????š???????Ϊ????ʱ??SF??ֵΪ0????????ֵΪ1??
6???????־OF(Overflow Flag)
?????־OF???ڷ?ӳ?з??????Ӽ????????ý???Ƿ?????????????????????ǰ????λ?????ܱ?ʾ?ķ?Χ?????Ϊ?????OF??ֵ????Ϊ1??????OF??ֵ????Ϊ0??
????????͡???λ??????????ͬ????ĸ????Ҫ???????????̫????Ļ???????ġ?????????ԭ?????γ??е??й??½ڡ?
????״̬???Ʊ?־λ
״̬???Ʊ?־λ??????????CPU?????ģ?????Ҫͨ??ר?ŵ?ָ?????ʹ֮?????ı䡣
1???ٱ?־TF(Trap Flag)
???ٱ?־TF????Ϊ1ʱ??CPU???뵥??ִ?з?ʽ????ÿִ??һ??ָ?????һ???????ж????????ַ?ʽ??Ҫ???ڳ???ĵ??ԡ?
ָ??ϵͳ??û??ר?ŵ?ָ?????ı??־λTF??ֵ????????Ա?????????취???ı???ֵ??
2???ж???????־IF(Interrupt-enable Flag)
?ж???????־IF??????????CPU?Ƿ???ӦCPU?ⲿ?Ŀ??????жϷ??????ж????????ܸñ?־Ϊ??ֵ??CPU????????ӦCPU?ⲿ?IJ????????ж??????????ж??????Լ?CPU?ڲ????????ж???????涨???£?
(1)????IF=1ʱ??CPU??????ӦCPU?ⲿ?Ŀ??????жϷ??????ж?????
(2)????IF=0ʱ??CPU????ӦCPU?ⲿ?Ŀ??????жϷ??????ж?????
CPU??ָ??ϵͳ??Ҳ??ר?ŵ?ָ?????ı??־λIF??ֵ??
3???????־DF(Direction Flag)
?????־DF?????????ڴ?????ָ??ִ??ʱ?й?ָ??Ĵ????????????ķ?????涨?ڵ?5.2.11?ڡ????ַ???????ָ????и???????????ָ??ϵͳ?У????ṩ??ר?ŵ?ָ?????ı??־λDF??ֵ??
???????????ÿ??һ???????ʾ??????־???????????????ÿ??һ????ֵ???ʾ??????־??????????Ϊ??????ĵ?????Ϣ??????????Ϊ???????е?ϵͳ?????˹??ϡ?????????ʱ??ϵ???????пͷ?????ʵ?????Ϣ???Ա㾡???????⡣
pos????ʾ??־(pos????ʾ????????ô????)POS????ʾ??־????ϸ˵??
1. ?????ɹ???ʾ??־????POS??ִ???û??????ɹ????????ɫ?Ĺ???ͼ?꣬???û?????????Ѿ??ɹ???ɵ???Ϣ?????ֱ?־???û??е????ģ?ȷ?????ǵ?ָ???ѱ???ȷ???ա?
2. ????ʧ????ʾ??־????POS???????ij?????ʱ??????ֺ?ɫ?IJ??ͼ?ꡣ??????????????????????????????ϻ?????????µġ????ֱ?־???û?֪????????Ҫ??ȡ?????ж?????????⡣
3. ?ȴ?״̬??ʾ??־????POS?????ڴ???ij??????ʱ???????һ????ת?е?Բ??ͼ???????ʾϵͳ???ڹ????У???????ҪһЩʱ????????????????????????ֱ?־???û?֪????????Ҫ?ȴ?һ??ʱ????ܻ?ý????
4. ??????ʾ??־????POS?????쳣???ʱ??????????????????ȣ?????ֻ?ɫ?????δ???̾?ŵ?ͼ??ʱ???û?Ӧ??ע?Ⲣ??ȡ??Ҫ??ʩ?Ա????һ?????ⷢ????
??֮????ʹ??POS??ʱ???˽??????ʾ??־?ĺ???dz???Ҫ??
????pos??????ʾ(pos??û????????־??ô????)1. ????pos??????ʾ??ԭ??
????pos??????ʾ?????????????¼?????????ɵģ?
- ?????????쳣?????????pos??û?????ӵ???????????????ʱ??ȡ???µĽ?????Ϣ??
- ϵͳ???ϣ?????pos?????ܻ????ϵͳ???ϣ?????????????????
- ???ô?????ʹ?ù????У??û????ܽ?ijЩ????ѡ??رջ??ߵ?????????????pos????????ʾ??
2. ??ν??????pos??????ʾ??????
???û?????????pos??????ʾ?????ʱ?????Բ?ȡ???½????ʩ??
- ??????????ӣ?????Ҫȷ??????pos???Ѿ????????ӵ????????????û?????ӣ?????Ҫ???????????????á?
- ?????豸?????????????pos??????ϵͳ???ϣ?????Գ????????豸???ָ????????С?
- ?鿴????ѡ??û???Ҫ??ϸ??????????ѡ???Ƿ???ȷ??????ȷ???Ƿ?????????????????⡣
3. ?û???α???????pos??????ʾ??????
????????????????ȡ?????ʩ???û??????Դ????¼???????Ԥ??????pos??????ʾ?????⣺
- ??ʱ??????????Ҫ????????pos???????????У??û???Ҫ???ڸ???????????ȷ??????????µĹ??ܺ????˿??ܴ??ڵ?©????
- ע??ʹ?û???????ʹ??????pos??ʱ??Ҫע??ʹ?û????Ƿ?????豸Ҫ????ʹ?ù??????ܵ??ⲿ???š?
- ??ȷ?????豸???û??ڲ???????pos??ʱӦ????ϸ?Ķ?˵???飬??????ָʾ???в?????????????????????⡣
4. ?ܽ?
????pos??????ʾ??һ???????????⣬????ֻҪ???Dz?ȡ??ȷ?Ľ????ʩ??Ԥ????ʩ?Ϳ?????Ч?????????????????ͬʱ?????ճ?ʹ????Ҳ??Ҫע?Ᵽ???豸??ȫ??????ʱ?????????汾??
