<html><head></head><body><div style="color:#000; background-color:#fff; font-family:Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><font id="yui_3_16_0_ym19_1_1495090222139_16711" face="verdana, helvetica, sans-serif">Matt Burke <matt@9track.net> wrote:<br id="yui_3_16_0_ym19_1_1495090222139_16583"><br id="yui_3_16_0_ym19_1_1495090222139_16584">> Whilst experimenting with a new device on VAX/VMS V4.5 I got a fatal<br id="yui_3_16_0_ym19_1_1495090222139_16585">> bugcheck (exception whilst above ASTDEL). The problem turned out the be<br id="yui_3_16_0_ym19_1_1495090222139_16586">> a reserved operand fault and I traced it back to the following code<br id="yui_3_16_0_ym19_1_1495090222139_16587">> (shown here from the VMS 3.0 source listings):<br id="yui_3_16_0_ym19_1_1495090222139_16588">> <br id="yui_3_16_0_ym19_1_1495090222139_16589">> MOVL PCB$L_PHD(R0),R0 ; Get PHD address<br id="yui_3_16_0_ym19_1_1495090222139_16590">> MOVB PHD$B_ASTLVL(R0),R0 ; And fetch ASTLVL<br id="yui_3_16_0_ym19_1_1495090222139_16591">> MTPR R0,#PR$_ASTLVL ; Update current value<br id="yui_3_16_0_ym19_1_1495090222139_16592"><br id="yui_3_16_0_ym19_1_1495090222139_16593">FWIW, the sequence does not appear to be present in 3.7-dev, 4.0 or 7.3 sources.<br id="yui_3_16_0_ym19_1_1495090222139_16594"><br id="yui_3_16_0_ym19_1_1495090222139_16595">(For 3.x and 4.x I checked only ASTDEL, not ASMP code -- speaking on which, would not it be fun to emulate 11/782 or 11/784?)<br id="yui_3_16_0_ym19_1_1495090222139_16596"><br id="yui_3_16_0_ym19_1_1495090222139_16597"></font><div id="yui_3_16_0_ym19_1_1495090222139_16764"><font id="yui_3_16_0_ym19_1_1495090222139_16711" face="verdana, helvetica, sans-serif">Is this exact sequence actually indicated by the instruction trace when running 4.5?<br></font></div><br><div id="yui_3_16_0_ym19_1_1495090222139_16617"><font face="verdana, helvetica, sans-serif">Thanks,</font></div><div id="yui_3_16_0_ym19_1_1495090222139_16619"><font face="verdana, helvetica, sans-serif">Sergey</font><br></div></div></body></html>