At 03:25 PM 8/8/2006 +0400, Arkady V.Belousov wrote: > MD> No, doesn't look right. A20 handling was turned off, > Japhet not tun off A20 handling, he just comment out call to INT67/3F.
Which turns off A20 handling enable/disable, unless it's resupported elsewhere. It's straight-forward logic flow on the INT 67h, function 3fh, along with a comment comparing to QEMM's internal use of the function. Commenting out deliberate function calls must have consequences, so the change was a pretty clearly a decision to turn off the global/local A20 handling at that point. >So, BL should be modified only in case of error. Not a big deal, I suggest >(I doubt, than someone will rely on untouched BL in case of success), but >worth of fixing (remove one line in source). No, I think it is proper to ensure that BL should be set to a nonerror code condition. I won't change the existing code and I think the spec interpretation is sufficient to support that behavior. > Non-error already indicated by AX=1 (and only by it). And I similarly > doubt, that (good) programmer will expect specific values in BL in case > of success (because specifications don't say about BL in case of AX=1). Unfortunately, nongood programs exist in abundance in DOS. I've seen several programs under the debugger, for example, check for any nonzero code when they should check for an exact code, although not specifically for this example. > Well, let test with MS-HIMEM: -a 11CA:0100 mov ax,4310 11CA:0103 > int 2f 11CA:0105 mov [100],bx 11CA:0109 mov [102],es 11CA:010D mov > bx,8080 11CA:0110 mov ah,5 11CA:0112 call far [100] 11CA:0116 int3 > 11CA:0117 -g=100 > AX=0001 BX=8000 CX=0000 DX=0000 SP=FFEE BP=0000 SI=0000 DI=0000 > --------------^^ Hm, it clears BL. I concur with MS, and in situation open to interpretation MS wins anyway for best backwards compatibility. ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Freedos-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
