Multibyte constant: Difference between revisions

From NESdev Wiki
Jump to navigationJump to search
(0xBEE52 is hex. 0xACTION52 is not unless it equals 0xFECE5.)
 
(.set was undocumented in old ca65; thefox told me about it in #nesdev)
Line 28: Line 28:
   .endif
   .endif
   .byte highdig * $10 + lowdig
   .byte highdig * $10 + lowdig
.endmacro
   ;.out .sprintf(".byte %02x", highdig * $10 + lowdig)
 
.macro mbyt_rgn inbytes, ifrom, ito
  ; Subdivide region into two, for O(log n) nested macros
   ; to make it more "5ca1ab1e"
  .if (ito - ifrom) > 2
    .local imid
    imid = (ifrom + (ito - ifrom) / 4 * 2)
    mbyt_rgn inbytes, ifrom, imid
    mbyt_rgn inbytes, imid, ito
  .elseif ito > ifrom
    mbyt_hex2nibs {.strat(inbytes, ifrom)}, {.strat(inbytes, ifrom + 1)}
  .endif
.endmacro
.endmacro


.macro mbyt inbytes
.macro mbyt inbytes
   .local len
  ; thanks to thefox who recommended .set
   len = .strlen(inbytes)
   .local pos
  mbyt_rgn inbytes, 0, len
  pos .set 0
  .out .sprintf("%s", inbytes)
   .repeat .strlen(inbytes)
    .if pos < .strlen(inbytes)
      nib .set .strat(inbytes, pos)
      ; these characters can be used as separators
      .if (nib = ' ' || nib = ',' || nib = '$' || nib = '_')
        pos .set pos + 1
      .else
        mbyt_hex2nibs nib, {.strat(inbytes, pos + 1)}
        pos .set pos + 2
      .endif
    .endif
  .endrepeat
.endmacro
.endmacro


; use it like this:
; use it like this:
; mbyt "ba5eba11"
; mbyt "09F91102 9D74E35B D84156C5 635688C0"
</source>
</source>


== External links ==
== External links ==
* [http://nedbatchelder.com/text/hexwords.html Ned Batchelder: Hex words] has test cases
* [http://nedbatchelder.com/text/hexwords.html Ned Batchelder: Hex words] has test cases

Revision as of 01:06, 17 November 2013

This macro allows including long hexadecimal constants on one line, like an arbitrary extension of the .dbyt (2 byte big endian constant). <source>

mbyt.s
Multibyte constant macro for ca65
Copyright 2013 Damian Yerrick
Copying and distribution of this file, with or without
modification, are permitted in any medium without royalty provided
the copyright notice and this notice are preserved in any source
code copies. This file is offered as-is, without any warranty.

.macro mbyt_hex2nibs highnib, lownib .local highdig, lowdig

 ; "dec0de" the hex nibbles
 .if highnib >= 'A' && highnib <= 'F'
   highdig = highnib - 'A' + 10
 .elseif highnib >= 'a' && highnib <= 'f'
   highdig = highnib - 'a' + 10
 .elseif highnib >= '0' && highnib <= '9'
   highdig = highnib - '0'
 .endif
 .if lownib >= 'A' && lownib <= 'F'
   lowdig = lownib - 'A' + 10
 .elseif lownib >= 'a' && lownib <= 'f'
   lowdig = lownib - 'a' + 10
 .elseif lownib >= '0' && lownib <= '9'
   lowdig = lownib - '0'
 .endif
 .byte highdig * $10 + lowdig
 ;.out .sprintf(".byte %02x", highdig * $10 + lowdig)

.endmacro

.macro mbyt inbytes

 ; thanks to thefox who recommended .set
 .local pos
 pos .set 0
 .out .sprintf("%s", inbytes)
 .repeat .strlen(inbytes)
   .if pos < .strlen(inbytes)
     nib .set .strat(inbytes, pos)
     ; these characters can be used as separators
     .if (nib = ' ' || nib = ',' || nib = '$' || nib = '_')
       pos .set pos + 1
     .else
       mbyt_hex2nibs nib, {.strat(inbytes, pos + 1)}
       pos .set pos + 2
     .endif
   .endif
 .endrepeat

.endmacro

use it like this
mbyt "09F91102 9D74E35B D84156C5 635688C0"

</source>

External links