HLASM Language Reference

Examples of Coded Machine Instructions
For most, the immediate value is treated as a signed binary integer (a value
between −32768 and +32767). This value may be specified using self-defining
terms or equated symbols.
┌────────┬────┬────┬─────────────────┐
│Op Code │ R │OpCd│ I │
└────────┴────┴────┴─────────────────┘
8 12 16 31
For logical instructions such as TMH, the immediate field is a 16 bit mask.
┌────────┬────┬────┬─────────────────┐
│Op Code │ M │OpCd│ I │
└────────┴────┴────┴─────────────────┘
8 12 16 31
Examples:
ALPHA1 AHI REG1,2
ALPHA2 MHI 3,1234
BETA1 TMH 7,X'81'
When assembled, the object code for the instruction labeled BETA1, in
hexadecimal, is
A7781
where:
A7. is the operation code
7 is register R
81 is the immediate data I2
For branching RI-format instructions, the immediate value is treated as a signed
binary integer representing the number of halfwords to branch relative to the current
location.
The branch target may be specified as a relocatable expression, in which case the
assembler performs some checking, and calculates the immediate value.
The branch target may also be specified as an absolute value in which case the
assembler issues a warning before it assembles the instruction.
Examples:
ALPHA1 BRAS 1,BETA1
ALPHA2 BRC 3,ALPHA1
BETA1 BRCT 7,ALPHA1
When assembled, the object code for the instruction labeled BETA1, in
hexadecimal, is
A776FFFC
where:
A7.6 is the operation code
7 is register R
FFFC is the immediate data I2; a value of −4 decimal
| If the GOFF assembler option is active, then it is possible to specify the target
| address as one or more external symbols (with or without offsets).
92 HLASM V1R5 Language Reference