x86 - How do I use CMP in assembly to test a segment and offset address? -

-

i want leave loop if current address i'm looking @ at least 0xffff0. here portion of code wrote, not work:

cmp ds:[bx], ffff0h jge leaveloop

i'm new assembly , have not used cmp more simple number comparisons.

this sounds xy problem, should have specified wanted achieve ultimately.

anyway, ffff0h 20 bit address, can't compare directly if limited 16 bits. can use 2 16 bit registers calculate physical address, , 32 bit comparison using those.

    mov ax, ds     mov dx, ds     shl ax, 4     shr dx, 12    ; dx:ax has segment base     add ax, bx    ; add offset     adc dx, 0     ; dx:ax has full address     cmp dx, 0fh   ; high word has @ least f     jb  false     ja  true      ; if it's more ok     cmp ax, fff0h ; low word has @ least fff0h     jae true false:     ... true:     ...

Comments

Post a Comment

Popular posts from this blog

android - questions about switching from C2DM to GCM -

-
i'm converting app c2dm gcm , have questions. i've modified gcmquickstart example found here: git clone https://github.com/googlesamples/google-services.git in class extends application, i've got: public class myapp extends application { @override public void oncreate() { super.oncreate(); if (this.checkplayservices()) { intent intent = new intent(this, registrationintentservice.class); startservice(intent); } else{ log.e(tag,"failed checkforgcm"); } } } afaik, starts service , it'll run forever or if operating system shuts down whereupon operating system restart it. correct? checkplayservices() makes sure android 2.3 or greater , google play services installed these requirements use gcm. correct? public class registrationintentservice extends intentservice{ private static final string tag = "regintentservice"; public registratio...
Read more

c++ - Qt setGeometry: Unable to set geometry -

-
why? setgeometry: unable set geometry 22x22+320+145 on qwidgetwindow/'widgetclasswindow'. resulting geometry: 116x22+320+145 (frame: 8, 30, 8, 8, custom margin: 0, 0, 0, 0, minimum size: 22x22, maximum size: 16777215x16777215). the project is: project.pro qt += core gui greaterthan(qt_major_version, 4): qt += widgets target = untitled5 template = app sources += main.cpp\ widget.cpp headers += widget.h widget.h #ifndef widget_h #define widget_h #include <qwidget> class widget : public qwidget { q_object public: explicit widget(qwidget *parent = 0); ~widget(); private: }; #endif // widget_h widget.cpp #include "widget.h" #include <qvboxlayout> widget::widget(qwidget *parent) : qwidget(parent) { qvboxlayout *vlayout = new qvboxlayout(this); } widget::~widget() { } main.cpp #include "widget.h" #include <qapplication> int main(int argc, char *argv[]) { qapplication a...
Read more

batch file - How to extract all multi-volume RAR archives from subfolders of a folder? -

-
i search way unpack multi-volume archives after download via batch. i download folders .r?? files in on ftp monitoring program , want winrar goes in first subfolder in source folder , start unpacking .r00, delete archive , move folder unpacked files new location. then batch script should start process again next subfolder. let's source folder c:\users\unpack contains following subfolders files: source folder subfolder1 archive1.r00 archive1.r01 archive1.r02 xxx.txt subfolder2 archive2.r00 archive2.r01 yyy.txt subfolder3 archive3.r00 archive3.r01 archive3.r02 archive3.r04 archive3.r05 zzz.txt i had start script in link below, script can't want, have started new question. how unpack rar archives in subfolders of folder , delete archives? the script in link above unrars files in subfolders , moves folder files new location. want script unrars , moves subfolder subfolder in source folder. edit.1 if winrar ready first subfolder s...
Read more