For now we just need something very simple for Getmain, Freemain and Abend processing. \u00a0This code will need to be updated but this will allow us to IPL and do some initial testing.<\/p>\n
000000 1 TXXGMAIN CSECT ,\r\n 00000 2 USING TXXGMAIN,R15\r\n 3 *\r\n000000 5410 F030 00030 4 N R1,=A(X'00FFFFFF') CLEAN UP LENGTH\r\n000004 4110 1007 00007 5 LA R1,7(,R1) ROUND UP TO DOUBLE WORD\r\n000008 5410 F034 00034 6 N R1,=A(X'00FFFFF8')\r\n 7 *\r\n00000C 5800 F01C 0001C 8 L R0,COREPTR\r\n000010 1B01 9 SR R0,R1\r\n000012 1810 10 LR R1,R0\r\n000014 5010 F01C 0001C 11 ST R1,COREPTR\r\n000018 1FFF 12 SLR R15,R15\r\n00001A 07FE 13 BR R14\r\n 14 *\r\n00001C 00100000 16 COREPTR DC A(1024*1024) 1M<\/pre>\nGetmain will round the requested length up to a double word value. \u00a0For now we will simply start at the 1 Meg mark and work backwards. \u00a0No attempt will be made to reuse memory when it is released via a Freemain. \u00a0This will allow us to IPL and run for a little while before we eventually start overlaying or Nucleus code.<\/p>\n
000000 1 TXXFMAIN CSECT ,\r\n 00000 2 USING TXXFMAIN,R15\r\n000000 07FE 3 BR R14 RETURN TO CALLER<\/pre>\nThe Freemain routine is very simple. \u00a0It simply returns to the caller.<\/p>\n
000000 1 TXXABEND CSECT ,\r\n 00000 2 USING TXXABEND,R15\r\n000000 8200 F008 00008 3 LPSW ERRPSW\r\n000008 4 DS 0D\r\n000008 00020000000BAD01 5 ERRPSW DC AL1(0,2,0,0),A(X'BAD01')<\/pre>\nThe Abend routine will simply load a wait state PSW.<\/p>\n
Although the code in these routines is not very robust it now gives us everything we need to link edit the Nucleus and IPL.<\/p>\n
[Next – Adding Some (Useful) Work To TXXDINIT<\/a>]<\/p>\n","protected":false},"excerpt":{"rendered":"
For now we just need something very simple for Getmain, Freemain and Abend processing. \u00a0This code will need to be updated but this will allow us to IPL and do some initial testing. 000000 1 TXXGMAIN CSECT , 00000 2 … Continue reading