Appendix G - Tachyon Legacy Assembler for MVS 3.8

This chapter describes the Tachyon Legacy Assembler for MVS 3.8. This is a special version of the assembler for use only on MVS 3.8 running on Hercules and for the purpose of developing programs that will be run in a System/370 or System/360 environment by the Hercules emulator.

Installing the assembler on MVS 3.8

The Tachyon Legacy Assembler for MVS 3.8 is provided in a ZIP file that contains the HTML version of the documentation and a TSO XMIT file named legacy.xmi for a load module library. The load module library is named TACHYON.LOADLIB in the XMIT file, but it may be renamed to any other data set name. TACHYON.LOADLIB contains a single load module named X390, which is the Tachyon Legacy Assembler program.

TACHYON.LOADLIB can be extracted from the legacy.xmi TSO XMIT file using either the dasdload program supplied with Hercules or the RECV370 program for MVS 3.8. Please see the appropriate documentation for these programs. TACHYON.LOADLIB has a block size of 18432 and so must be loaded to a 3350, 3380 or 3390 volume.

Before the Tachyon Legacy Assembler can be run, the license information must be installed into the TACHON.LOADLIB load library as a load module named TACHYON. The license key information for the Tachyon Legacy Assembler for MVS 3.8 is in the form of JCL that must be executed to assemble and linkedit the license information module.

Running the assembler on MVS 3.8

The Tachyon Legacy Assembler for MVS 3.8 can be invoked via JCL or from via the LINK or ATTACH services. The program name is installed as X390, but can be renamed to another name such as IFOX00, IEV90 or ASMA90.

Invoking the assembler via JCL

Sample JCL:

//TACHYON  JOB
//ASM      EXEC PGM=X390,REGION=8M,PARM='LOAD,ASA,SIZE(3M)'
//STEPLIB  DD DSN=TACHYON.LOADLIB,DISP=SHR
//SYSPRINT DD SYSOUT=*
//SYSTERM  DD SYSOUT=*
//SYSLIB   DD DSN=SYS1.MACLIB,DISP=SHR
//         DD DSN=SYS1.AMODGEN,DISP=SHR
//SYSGO    DD DSN=&&GOSET,DISP=(NEW,PASS,DELETE),
// UNIT=SYSDA,SPACE=(CYL,(1,1)),
// DCB=(DSORG=PS,LRECL=80,BLKSIZE=3200,RECFM=FB)
//SYSUT1   DD DSN=&&SYSUT1,DISP=(NEW,DELETE,DELETE),
// UNIT=VIO,SPACE=(CYL,(10,10)),DCB=(DSORG=PS)
//SYSUT2   DD DSN=&&SYSUT2,DISP=(NEW,DELETE,DELETE),
// UNIT=VIO,SPACE=(CYL,(10,10)),DCB=(DSORG=PS)
//SYSUT3   DD DSN=&&SYSUT3,DISP=(NEW,DELETE,DELETE),
// UNIT=VIO,SPACE=(CYL,(10,10)),DCB=(DSORG=PS)
//SYSIN    DD *
IEFBR14  CSECT
         SR    15,15
         BR    14
         END   IEFBR14
/*
//

Note: The REGION size should be as large as possible to improve performance of the assembler. The default of SIZE(MAX) improves performance, but it can cause the assembly to fail if it cannot be performed in memory. If the assembly is too large to be performed in memory, specify a SIZE option that is no more than half of the region size. For very large assemblies, SIZE(0) has been found to cause the assembler to run almost as fast as any other value less than SIZE(MAX) and provides the maximum opportunity for assemblies to complete successfully.

Invoking the assembler via LINK or ATTACH

The assembler program can be invoked via the MVS LINK or ATTACH services. When invoked, general register 1 must contain the address of a parameter list. The parameter list must consist of one or two words, with the high-order bit of the last word set on.

The first parameter list word must contain the address of a halfword containing the number of characters which follow, followed by a string containing the assembler options. The options may be zero to 32767 characters.

If present, the second parameter list word must contain the address of a halfword containing the number of characters in the DDNAME override list, followed by the DDNAME override list. The DDNAME override list can consist of zero or more 8-character entries. Unused entries must be set to binary zeros. If an entry is not binary zeros, the 8-character name will be used as the DDNAME instead of the default DDNAME. The DDNAME override entries are:

Entry	Offset	Default DDNAME
1	+0	SYSLIN or SYSGO
2	+8	not used
3	+16	not used
4	+24	SYSLIB
5	+32	SYSIN
6	+40	SYSPRINT
7	+48	SYSPUNCH
8	+56	SYSUT1
9	+64	SYSUT2
10	+72	SYSUT3
11	+80	not used
12	+88	SYSTERM
13	+96	not used
14	+104	not used
15	+112	not used
16	+120	SYSADATA
17	+128	not used
18	+136	not used
19	+144	not used
20	+152	ASMAOPT

Input, Output and Work Files

SYSIN

The open-code assembler source statements are read from SYSIN. The source statements must be 80-byte fixed length records from one or more concatenated files, each of which can be an in-stream data set, a sequential data set or a partitioned data set member. The SYSIN DD is required.

SYSLIB

Macros and copy members are read from SYSLIB. SYSLIB must be one or more concatenated partitioned data sets with 80-byte fixed-length records. The SYSLIB DD is not required if there are no COPY statements or macro calls.

ASMAOPT

Assembler options will be read from ASMAOPT if the DD is present. ASMAOPT must consist of one or more concatenated files, each of which can be an in-stream data set, a sequential data set or a partitioned data set member. Fixed, variable and undefined record length of any size are allowed. Any options read from ASMAOPT are processed before the options from the EXEC PARM are processed.
Each record read from ASMAOPT may be blank, may be a comment line, or may contain one option. If the first non-whitespace character is an asterisk (*), it is assumed to be a comment line and is not processed. If the first non-whitespace character is not an asterisk, it is assumed to contain an option. To provide a comment on an option line, follow the option by at least one blank, the remainder of the line will then be ignored.

SYSLIN or SYSGO

If one of the OBJECT(OMF), OBJECT(XOBJ) or OBJECT(GOFF) options are active, the object code will be written to SYSLIN or SYSGO, depending on which is allocated. SYSLIN or SYSGO must be defined for 80-byte fixed length records and should be a sequential data set or partitioned data set member.

SYSPUNCH

If the OBJECT(DECK) option is active, the object code will be written to SYSPUNCH. SYSPUNCH must be defined for 80-byte fixed length records and should be a sequential data set or partitioned data set member.

SYSPRINT

If the LIST option is active, the assembly listing will be written to SYSPRINT. SYSPRINT must be defined for 121 to 133 byte fixed-length records or 125 to 137 byte variable-length records with either ASA or machine control characters. The record length must be 133 for fixed-length or 137 for variable-length if the LIST(133) option is set. SYSPRINT can be allocated to a SYSOUT data set, sequential data set or partitioned data set member.

SYSTERM

If the TERM option is active, assembly messages will be written to SYSTERM. SYSTERM may be defined as for fixed, variable or undefined length records and should be a SYSOUT data set or sequential data set. If an error prevents the assembler from starting, messages will be written to SYSTERM and therefore, SYSTERM should always be defined.

SYSADATA

If the ADATA option is active, ADATA records will be written to SYSADATA. SYSADATA must be defined for variable length records of at least 8188 bytes and should be a sequential data set.

SYSUT1, SYSUT2 and SYSUT3

These work files are used when the memory specified via the SIZE option is exhausted. If DD statements for any of these files are not present, data sets named &&SYSUT1, &&SYSUT2 and &&SYSUT3 will be dynamically allocated. The DD statements should be present if the default SPACE allocations are insufficient. The default allocations are for a primary and secondary space of 100 tracks on unit SYSALLDA.

Assembler Option Support Differences

Assembler Language Support Differences

Most of the assembler language supported by the Tachyon z/Assembler is fully supported by the Tachyon Legacy Assembler for MVS 3.8, except for the following:

• *PROCESS and *ASM.
• AMODE 64, AMODE ANY64 and RMODE 64
• CATTR and XATTR
• ACONTROL AFPR and ACONTROL NOAFPR
• Assembler types AR, CR64 and GR64 for the fifth EQU operand.
• Binary floating point (EB, DB, LB) and decimal floating point (ED, DD, LD) storage definitions and literals
• CA, CB, CE, CU and CW storage definitions, literals and self-defining terms
• Quadword binary (FQ and LQ) storage definitions and literals.
• Doubleword address (AD, JD, RD, QD and VD) storage definitions and literals
• The maximum control section size is X'00FFFFFF'.

External functions called via SETAF and SETCF are only supported in the MVS version of the assembler.

Except as noted above, the language compatibility notes and language extensions notes apply to the Tachyon Legacy Assembler.