told .. " \,Q ,:: H (1) INPUT - 0 TRACE XXX Cl VMBLOK .... H r+ ,:: pt VMTRCTL .. VMTREXT "3 H pt n .... =' \,Q Entered From OMKCFM
After 'TRACE' Command
Entered
_O_M __ K_TR_A ______ PROCESS __________________ Pick up operands and options and check for validity If 'OFF' specified, turn off flags .......... .. If 'END' specified, call DMKTRCPBto restore any instructions altered by TRACE, turn off flags, and'
return TREXT block to free storage ........ .
Otherwise, Issue 'TRACE STARTED' message
Get trace control block and set VMBLOK
pointer to it, if a trace control block does •••• ' not exist. Set trace flags. Call DMKTRCIT to
initialize branch or full in!,truction tracing,
if
Entry via SVC 8 8 ----------PROCESS -------------......,
Put trace prefix and type in output line Convert binary addresses to hexadecimal (DMKCVT)
Get mnemonic for OP code, if applicable (DMKNEM)
Write trace line to output device If ATTN was pressed or if halt after trace line.w.a.s.sp.e.ci.fie.d ........ enter console function mode and ex it
Entered from OM KC FM after AOSTOP' command entered
OMKCFOAO
Otherwise, , Get work buffer
Set VMBLOK pointer Save instruction and its virtual add.reiis.s ..... Replace instruction with SVC B3 OUTPUT---------------,---, VMBLOK OUTIPUT Virtual Storage
[
TREXT TFIEXCTLli TFIEXCTL2 TREXTERM
TFlEXPRNT
TREXRUNF COMMENTS If this turns off the last flag, then the TREXT block
is returned to free storage. If branch and instruction
tracing are both turned off, ClMKTRCPB is called to put back any instructions altered by TRACE,
VMTRCTL and TREXCTL 1 are identical. e Entry via SVC 8 as follows Entry Point From External Interrupt DMKTRCEX DMKDSP 11/0 Interrupt DMKTRCIO DMKDSP Program Interrupt DMKTFlCPG DMKPRG Privileged Instructions DMKTRCPV DMKPRV 'I/O Operatiol')s DMKTRDSI DMKVIOEX Virtual and Real CSWs DMKTRCSW DMKVIOIN SVC, branch or full DMKTRCSV DMKPSA instruction trace
Restore user instructions DMKTRCPB DMKTRA
altered by tracing Initialize instruction tracing DMKTIlCIT DMKTRA
... "Id I .... II.) \Q 01:' c: t1 CD H td ... =- ... C3 =- " C3 W .... ..... t1 0 t+ c: UJ PI .... .. EO t+ t+ CD 'f t'" CD 0 lit \Q ..... n \l1li' PI at P- I:' t1 PI CD (II I'd (II t1 0 1-3 t:r t1 ..... lit CD t:I EO ..... t:=- Ilt CD t+ t+ .... CD 0 t1 t:I .... t:I lit t+ .... 0 t:I I C3 0 ..... c: CD .... Virtual Address LOCATE THE SEGMENT TABLE
Segment Table Register ICR 1) I Segme.nt Table I Ongm 8 25 26 31
31
Page Table LOCATE PAGE
TABLE USE AS INDEX TO PAGE TABLE
ENTRY
Real Address Translate Virtual Addres' 00080424 to Real Address
/
( I I I I I I I I I I Virtual Address "..--;---+-----1 1 J Locate the appropriate Segment Table entry . The eighth entry in
the Segment Table at location 014440 This entry points to the Page Table. ...- 014440 I I I I ;' II Locate the appropriate Page Table entry -/
The 13th entry in the Page Table at _ __ I r-I-..I.-----r--'----. 012 Real Address location 014440. This entry contains ,''- ____ --'- _____ -' the real block number. / Block Displacement / The block number in the Page __ J Table entry and the displacement in
Number
the Virtual Address combine to provide the Real Address
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