SETB     .MACRO  .B,.D
         LDA .B
         TSB .D
         .ENDM

;KOWALSKI SIMULATOR ASSEMBLER DIRECTIVES — BigDumbDinosaur (revised 2012/07/01)

 IO_AREA           ;define console I/O area address (no leading dot in IO_AREA)
 .ASCII .BYTE .DB  ;generate static data, such as strings, tables, etc.
 .ASCIS            ;generate character string w/bit 7 of last byte set
 .DBYTE .DD        ;assemble big-endian word
 .DCB              ;equivalent to * = * + N, where N is arg to .DCB,...
                   ;w/optional initialization pattern, e.g., .DCB 10,$FF, which will
                   ;reserve 10 bytes & fill them with $FF
 .DS .RS           ;equivalent to * = * + N, where N is arg to .DS or .RS
 .DW .WORD         ;assemble little-endian word
 .ELSE             ;conditional assembly directive
 .END              ;mark end of source file, optional
 .ENDIF            ;mark end of conditional assembly
 .ENDM             ;mark end of macro definition
 .ENDR             ;mark end of repeated text
 .ERROR            ;emit an error message & halt assembly, e.g., .ERROR "!!! operand out of range !!!"
 .EXITM            ;halt macro expansion
 .IF               ;start conditional assembly
 .INCLUDE          ;insert contents of named source file, e.g., .INCLUDE "include\atomic.65s"
 .IO_WND           ;define console I/O window size (cols, rows)
 .MACRO            ;mark start of macro definition, w/optional comma-separated parameters
 .OPT              ;set global assembly options
 .ORG              ;set start of assembly address, same as * = <addr>
 .PARAMTYPE        ;determine macro parameter type: 1 = numeric, 2 = string,...
                   ;.IF .PARAMTYPE(.op) == 1
 .REF              ;determine if label/symbol was defined,...
                   ;e.g., .IF .REF(ABC) evaluates true if ABC has been defined; logic can be reversed with !.REF (ABC)
 .REPEAT .REPT     ;repeat following text, e.g., .REPT 5
 .ROM_AREA         ;set simulator's write-protected address range
 .SET              ;(re)define variable value, e.g., X .SET 1 allows X to be redefined by a later .SET.  .= is a synonym for .SET
 .START            ;set simulator start of execution address
 .STR .STRING      ;generate text string, 1st byte is length, 255 bytes maximum
 .STRLEN           ;determine macro parameter string length

.IF evaluations can use the following binary operators:

    ==  "is equal to"
    !=  "is not equal to"
    >   "is greater than"
    <   "is less than"

.IF .X means "if .X is non-zero".

;===============================================================================
;
;scsicmd: EXECUTE SCSI COMMAND
;
;   ———————————————————————————————————————————————————————————————
;   Preparatory Ops : .A:  8 bits: target device SCSI ID
;                     .X: 16 bits: command descriptor block address
;                     .Y: 16 bits: buffer address (1)
...more comments follow...
;
scsicmd  rep @11111111         ;clear all SR flags

 ; The next few words starting with U go faster than their non-U counterparts
 ; by avoiding M/MOD above.  Use them to speed up execution when you're using
 ; unsigned numbers or when you know the inputs will never be negative.

        HEADER "U/MOD", NOT_IMMEDIATE   ; ( u1 u2 -- rem quot )
UsMOD:  DWL     nest, ZERO, SWAP, UMsMOD, unnest
 ;-------------------

        HEADER "/", NOT_IMMEDIATE       ; ( n1 n2 -- quot )
SLASH:  DWL     nest, sMOD, NIP, unnest
 ;-------------------

        HEADER "U/", NOT_IMMEDIATE      ; ( u1 u2 -- quot )
Uslash: DWL     nest, UsMOD, NIP, unnest
 ;-------------------

        HEADER "MOD", NOT_IMMEDIATE     ; ( n1 n2 -- rem )
MOD:    DWL     nest, sMOD, DROP, unnest
 ;------------------

        HEADER "UMOD", NOT_IMMEDIATE    ; ( u1 u2 -- rem )
UMOD:   DWL     nest, UsMOD, DROP, unnest
 ;-------------------

        HEADER "*/MOD", NOT_IMMEDIATE   ; ( n1 n2 n3 -- rem quot )
ssMOD:  DWL     nest, TO_R, Mstar, R_FR, MsMOD, unnest
 ;-------------------

        HEADER "U*/MOD", NOT_IMMEDIATE  ; ( u1 u2 u3 -- rem quot )
UssMOD: DWL     nest, TO_R, UMstar, R_FR, UMsMOD, unnest
 ;-------------------

        HEADER "*/", NOT_IMMEDIATE      ; ( n1 n2 n3 -- n1*n2/n3 )
STARSLASH: DWL  nest, ssMOD, NIP, unnest
 ;-------------------

        HEADER "U*/", NOT_IMMEDIATE     ; ( u1 u2 u3 -- u1*u2/u3 )
USTARSLASH: DWL nest, UssMOD, NIP, unnest
 ;-------------------