Multibyte constant

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

.endmacro

.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

.macro mbyt inbytes

 .local len
 len = .strlen(inbytes)
 mbyt_rgn inbytes, 0, len

.endmacro

use it like this

mbyt "ba5eba11"

</source>

External links

• Ned Batchelder: Hex words has test cases