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zasm - Z80 Assembler – Version 4.4

Pseudo instructions

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Label definition

--reqcolon

--dotnames

--casefold

Types of labels

<name>[:][:] [<instruction>]
<name>[:][:] Pseudo instructions: equ
Types of labels: Named values
Labels: EQUequ  <value>
<name>[:][:] =    <value>
<name>[:][:] Pseudo instructions: defl, set and '='
Labels: SETset  <value>
<name>[:][:] defl <value>
#define <name>    <value>

Pseudo instructions: Label definition
Numeric expressions: Labels
8080 Assembler: LabelsLabel names may be of any length. Upper or lower case is distinguished. The Pseudo instructions: Label definition
Numeric expressions: Labels
8080 Assembler: Labelslabel name may be followed by one or two colons ':'.

Normally, label definitions must start in column 1 and instructions must be indented with some spaces. The assembler decides based on the starting column of a name whether it is a label definition or an instruction.

Any name which starts in column 1 and is not an assembler directive (which always starts with a hash '#') or a comment (which always starts with a semicolon ';') is treated as a label definition.

unless --Command Line Options: --dotnames, .dotnames
Commands for command line options: --dotnames, .dotnames
Label definition: --dotnamesdotnames is also Pseudo instructions: defl, set and '='
Labels: SETset, Pseudo instructions
8080 Assembler: 8080 pseudo instructionspseudo instructions starting with a dot are also recognized in column 1.

--reqcolon

Assembler directives: #if, #elif, #else, #endif
Pseudo instructions: if, endifIf the source is assembled with Differences from v3 to v4: Command line options
Command Line Options
Command Line Options: Command line optionscommand line option '--reqcolon', then one colon is required after the Pseudo instructions: Label definition
Numeric expressions: Labels
8080 Assembler: Labelslabel name. This allows label definitions to start in any column, either in column 1 as usual or indented with some spaces and tabs, and it allows instructions to start in column 1. The assembler decides based on the existance or absence of a colon whether it is a label definition or an instruction.
Note: even with --reqcolon no colon is required after Pseudo instructions: Label definition
Numeric expressions: Labels
8080 Assembler: Labelslabels defined with 'Pseudo instructions: equ
Types of labels: Named values
Labels: EQUequ' and similar.

Recommendation: Start label definitions in column 1, indent instructions with one or two tabs and put a colon after label definitions.

--dotnames

Normally Pseudo instructions: Label definition
Numeric expressions: Labels
8080 Assembler: Labelslabel names cannot start with a dot. Names starting with a dot were introduced by some assemblers to easily distinguish betwen Pseudo instructions: Label definition
Numeric expressions: Labels
8080 Assembler: Labelslabel names, instructions and assembler Pseudo instructions
8080 Assembler: 8080 pseudo instructionspseudo instructions, so these could be written in column 1 Assembler directives: #if, #elif, #else, #endif
Pseudo instructions: if, endifif the programmer desired so. Having seen that, some people immediately developed the need to start their Pseudo instructions: Label definition
Numeric expressions: Labels
8080 Assembler: Labelslabel names with a dot as well…

Recommendation: Don't start Pseudo instructions: Label definition
Numeric expressions: Labels
8080 Assembler: Labelslabel names with a dot.

--casefold

Normally Pseudo instructions: Label definition
Numeric expressions: Labels
8080 Assembler: Labelslabel names are case sensitive or people just tend to just write them allways in the same way.

Assembler directives: #if, #elif, #else, #endif
Pseudo instructions: if, endifIf an older source does not distinguish between uppercase and lowercase writing of Pseudo instructions: Label definition
Numeric expressions: Labels
8080 Assembler: Labelslabel names, then you can use this option to tell zasm to ignore upper and lower case as well.

Note: instruction and register names are always case insensitive.

This option is implied by --asm8080.

Recommendation: Don't use this option unless required.

Types of labels

        Program labels
        <name>[:][:] [<instruction>]

        Types of labels: Program labels
        Types of labels: Program labels        Program labels basically are what we just talked about: A name put in front of an instruction to give the current code position a name so that it can be used in a later call or jp statement.

        foo:    jp  _bar

        This defines a Types of labels: Program labels
        Types of labels: Program labels        program label named 'foo' and the instruction jumps to a Pseudo instructions: Label definition
        Numeric expressions: Labels
        8080 Assembler: Labels        label named '_bar' which is likely a Types of labels: Program labels
        Types of labels: Program labels        program label as well.

        The address of the current instruction can also be referenced as '$', so in some easy cases you don't need to define a Pseudo instructions: Label definition
        Numeric expressions: Labels
        8080 Assembler: Labels        label.

        Assembler directives: #if, #elif, #else, #endif
        Pseudo instructions: if, endif        If you request that your list file includes accumulated cpu cycles, then the counter is reset at every Types of labels: Program labels
        Types of labels: Program labels        program label definition.

        Named values
        <name>[:][:] Pseudo instructions: equ
        Types of labels: Named values
        Labels: EQU        equ  <value>
<name>[:][:] =    <value>
#define <name>    <value>

        Frequently you start your source with a bunch of definitions for constant values, like printing control codes or port addresses. These definitions require the keyword 'Pseudo instructions: equ
        Types of labels: Named values
        Labels: EQU        equ' after the Pseudo instructions: Label definition
        Numeric expressions: Labels
        8080 Assembler: Labels        label, in exchange a colon after the label name is never required, even with --reqcolon, but may be present.

        foo     Pseudo instructions: equ
        Types of labels: Named values
        Labels: EQU        equ 255 -1
bar     Pseudo instructions: equ
        Types of labels: Named values
        Labels: EQU        equ 255 -2
shelf   =   0xffff
#define foobar foo & bar

        Most assemblers require keyword 'Pseudo instructions: equ
        Types of labels: Named values
        Labels: EQU        equ', some use '='. The use of 'Pseudo instructions: equ
        Types of labels: Named values
        Labels: EQU        equ' is recommended.

        Additionally zasm supports the use of the c preprocessor-style definition using '#define'.

        Redefinable named values
        <name>[:][:] Pseudo instructions: defl, set and '='
        Labels: SET        set  <value>
<name>[:][:] defl <value>

        Especially for use in Pseudo instructions: macro, .macro, endm and .endm
        8080 pseudo instructions: MACRO        macros it is possible to define Pseudo instructions: Label definition
        Numeric expressions: Labels
        8080 Assembler: Labels        labels which can be redefined to another value. These definitions require the keyword 'Pseudo instructions: defl, set and '='
        Labels: SET        set' or 'defl' after the Pseudo instructions: Label definition
        Numeric expressions: Labels
        8080 Assembler: Labels        label, in exchange a colon after the Pseudo instructions: Label definition
        Numeric expressions: Labels
        8080 Assembler: Labels        label name is never required, even with --reqcolon, but may be present.
        Note: don't confuse the 'Pseudo instructions: defl, set and '='
        Labels: SET        set' Pseudo instructions
        8080 Assembler: 8080 pseudo instructions        pseudo instruction with the Command Line Options: --z80
        Pseudo instructions: .z80, .z180 and .8080
        Targets: #target Z80        Z80's 'Pseudo instructions: defl, set and '='
        Labels: SET        set' instruction!

        This defines a Pseudo instructions: macro, .macro, endm and .endm
        8080 pseudo instructions: MACRO        macro which counts the occurances of something:
        Note: the final count is only valid after the last use of this Pseudo instructions: macro, .macro, endm and .endm
        8080 pseudo instructions: MACRO        macro in your source!

        foo     Pseudo instructions: defl, set and '='
        Labels: SET        set 0
        Pseudo instructions: macro, .macro, endm and .endm
        8080 pseudo instructions: MACRO        macro COUNT
foo     Pseudo instructions: defl, set and '='
        Labels: SET        set foo+1
        Pseudo instructions: macro, .macro, endm and .endm
        Pseudo instructions: rept, .rept, endm and .endm        endm

        Use of a redefinable Pseudo instructions: Label definition
        Numeric expressions: Labels
        8080 Assembler: Labels        label in place of a Types of labels: Program labels
        Types of labels: Program labels        program label:
        Note: forward jumping can't be implemented this way!

                Pseudo instructions: macro, .macro, endm and .endm
        8080 pseudo instructions: MACRO        macro WAIT &N
        ld      b,&N
foo     defl    $
        call    wait_1ms
        djnz    foo
        Pseudo instructions: macro, .macro, endm and .endm
        Pseudo instructions: rept, .rept, endm and .endm        endm

        The value is valid from the position where it was defined to the position where it is redefined or the Pseudo instructions: end, .end
        8080 pseudo instructions: END        end of the source. References to this Pseudo instructions: Label definition
        Numeric expressions: Labels
        8080 Assembler: Labels        label before it's first definition are illegal!

        global labels

        Pseudo instructions: Label definition
        Numeric expressions: Labels
        8080 Assembler: Labels        Labels are defined in the current 'scope', which is either the default global scope or, after Assembler directives: #local, #endlocal, .local and .endlocal
        Pseudo instructions: #local, #endlocal, .local and .endlocal
        Including C Source Files: #local, #endlocal, .local and .endlocal        #local, a Assembler directives: #local, #endlocal, .local and .endlocal
        Pseudo instructions: #local, #endlocal, .local and .endlocal
        Including C Source Files: #local, #endlocal, .local and .endlocal        local scope.

        Normally Pseudo instructions: Label definition
        Numeric expressions: Labels
        8080 Assembler: Labels        labels defined after Assembler directives: #local, #endlocal, .local and .endlocal
        Pseudo instructions: #local, #endlocal, .local and .endlocal
        Including C Source Files: #local, #endlocal, .local and .endlocal        #local are only known in the Assembler directives: #local, #endlocal, .local and .endlocal
        Pseudo instructions: #local, #endlocal, .local and .endlocal
        Including C Source Files: #local, #endlocal, .local and .endlocal        local scope:

        Assembler directives: #local, #endlocal, .local and .endlocal
        Pseudo instructions: #local, #endlocal, .local and .endlocal
        Including C Source Files: #local, #endlocal, .local and .endlocal        #local
foo:    nop
        ...
        jr  foo
Assembler directives: #local, #endlocal, .local and .endlocal
        Pseudo instructions: #local, #endlocal, .local and .endlocal
        Including C Source Files: #local, #endlocal, .local and .endlocal        #endlocal

        You can also define global labels inside a Assembler directives: #local, #endlocal, .local and .endlocal
        Pseudo instructions: #local, #endlocal, .local and .endlocal
        Including C Source Files: #local, #endlocal, .local and .endlocal        local scope:
        Just put two colons '::' after the Pseudo instructions: Label definition
        Numeric expressions: Labels
        8080 Assembler: Labels        label name or use the Pseudo instructions
        8080 Assembler: 8080 pseudo instructions        pseudo instruction '.globl':

        Assembler directives: #local, #endlocal, .local and .endlocal
        Pseudo instructions: #local, #endlocal, .local and .endlocal
        Including C Source Files: #local, #endlocal, .local and .endlocal        #local
        .globl  bar
foo::   nop             ; global
        ...
bar:    nop             ; global
        ...
shelf:: Pseudo instructions: equ
        Types of labels: Named values
        Labels: EQU        equ foo+1       ; global
Assembler directives: #local, #endlocal, .local and .endlocal
        Pseudo instructions: #local, #endlocal, .local and .endlocal
        Including C Source Files: #local, #endlocal, .local and .endlocal        #endlocal
        Reusable labels

        zasm supports the 'recyclable' Pseudo instructions: Label definition
        Numeric expressions: Labels
        8080 Assembler: Labels        labels used by sdcc:

        foo::
        ...
123$:   nop
        jp  123$
        jp  199$
199$:   nop
        ...
bar::
        ...
123$:   nop
        ...

        The name of a reusable label is only valid in the range between two normal Types of labels: Program labels
        Types of labels: Program labels        program labels.
        The naming scheme is a little but unlucky. Assembler directives: #if, #elif, #else, #endif
        Pseudo instructions: if, endif        If you put a dollar sign '$' after a number it becomes a Pseudo instructions: Label definition
        Numeric expressions: Labels
        8080 Assembler: Labels        label name. :-/

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