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| author | Kartik Agaram <vc@akkartik.com> | 2018-12-06 12:27:06 -0800 |
|---|---|---|
| committer | Kartik Agaram <vc@akkartik.com> | 2018-12-06 12:27:06 -0800 |
| commit | 24e3796c23d0729fbe798bb51e2b5c3cb682ff47 (patch) | |
| tree | d7daf22298cba3a4552237173416562f92431d84 /subx/apps/hex.subx | |
| parent | b94863fdf2657f27b73eca09f5d1c4824cf54532 (diff) | |
| download | mu-24e3796c23d0729fbe798bb51e2b5c3cb682ff47.tar.gz | |
4853
Diffstat (limited to 'subx/apps/hex.subx')
| -rw-r--r-- | subx/apps/hex.subx | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/subx/apps/hex.subx b/subx/apps/hex.subx index 8155a1c5..3cb1a005 100644 --- a/subx/apps/hex.subx +++ b/subx/apps/hex.subx @@ -1,5 +1,6 @@ -# Read a text file containing whitespace-separated ascii hex bytes from stdin, -# and convert them into a binary file. +# Read a text file containing whitespace-separated pairs of ascii hex bytes +# from stdin, and convert them into binary bytes (octets) on stdout. Ignore +# comments between '#' and newline. # # To run (from the subx/ directory): # $ ./subx translate *.subx apps/hex.subx -o apps/hex @@ -86,11 +87,11 @@ $convert:end: 5d/pop-to-EBP c3/return -# read bytes from 'in' until a sequence of two lowercase hex characters (0-9, a-f) +# read bytes from 'in' until a sequence of two lowercase hex (0-9, a-f) bytes # skip spaces and newlines # on '#' skip bytes until newline # raise an error and abort on all other unexpected bytes -# return the binary value of the two hex characters in EAX +# return in EAX an _octet_ containing the binary value of the two hex characters # return 0xffffffff on end of file convert-next-hex-byte: # in : (address buffered-file), err : (address buffered-file), ed : (address exit-descriptor) -> byte-or-eof/EAX # pseudocode: @@ -156,7 +157,7 @@ $convert-next-hex-byte:end: c3/return test-convert-next-hex-byte: - # - check that the first two bytes of the input are assembled into the resulting number + # - check that the first two bytes of the input are assembled into the resulting octet # This test uses exit-descriptors. Use EBP for setting up local variables. 55/push-EBP 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP |