A skool file template defines the basic structure of a skool file, but, unlike a skool file, contains directives on how to disassemble a program into Z80 instructions instead of the Z80 instructions themselves. The directives are similar to those that may appear in a control file.
The skool2sft.py command can generate a skool file template from an existing skool file; the sna2skool.py command can then generate a skool file from the template and an appropriate snapshot.
A skool file template has the same layout as a skool file, except that the lines in b, c, g, s, t, u and w blocks that correspond to Z80 instructions look like this:
xX#####,N[;c[ comment]]
where:
If a comment for a single instruction spans two or more lines in a skool file, as in:
c24296 CALL 57935 ; This comment is too long to fit on a single line, so
; we use two lines
then it will be rendered in the skool file template thus:
cC24296,3;21 This comment is too long to fit on a single line, so
;21 we use two lines
The syntax for specifying B, C, S, T and W sub-blocks is analogous to the syntax used in control files. A brief summary of the syntax is given here.
Sequences of DEFB statements can be declared on a single line by a comma-separated list of sublengths thus:
bB40960,8*2,5
which is equivalent to:
bB40960,8
B40968,8
B40976,5
The same syntax also applies for declaring sequences of DEFM, DEFS and DEFW statements.
DEFB and DEFM statements may contain both strings and bytes; for example:
b30000 DEFB 1,2,3,4,"Hello!"
30010 DEFM 5,6
30012 DEFM "B",7,8
Such statements are preserved in a skool file template thus:
bB30000,4:T6
T30010,B2,1:B2
DEFB, DEFM, DEFS and DEFW statements may contain numeric values in various bases or as characters. For example:
b40000 DEFB %10101010,23,43,$5F
40004 DEFB 56
40005 DEFB %11110000
40006 DEFB $2B,$80
40008 DEFS 8,"!"
These statements may be preserved in a skool file template thus:
bB40000,b1:d2:h1,d1,b1,h2
S40008,8:c"!"
Instruction operands may also contain numeric values in various bases or as characters. For example:
c50000 LD A,%00011000
50002 LD B,"!"
50004 LD (IX+$1A),%00001111
These instructions may be preserved in a skool file template by using b (binary), c (character), d (decimal) and h (hexadecimal) prefixes on sublength parameters thus:
cC50000,b2,c2,hb4
Any line that begins with a hash character (#) is ignored by sna2skool.py, and will not show up in the skool file.
In the same way as skool2html.py uses data definition entries (‘d’ blocks) in a skool file to insert data into the memory snapshot it constructs, sna2skool.py uses data definition entries in a skool file template to replace data in the snapshot given on the command line. This feature can be used to make sure that a ‘volatile’ part of memory is set to a specific value before being disassembled.
For example, if address 32400 holds the number of lives, you could make sure that its contents are set to 0 so that it will disassemble to DEFB 0 (whatever the contents may be in the snapshot itself) thus:
d32400 DEFB 0
; Number of lives
bB32400,1
Note that in order to take effect, a ‘d’ block must appear before the block that it overrides.
| Version | Changes |
|---|---|
| 4.5 | Added support for specifying character values in DEFS statements |
| 4.4 | Added support for specifying that numeric values in instruction operands be rendered as characters or in a specific base; added support for specifying character values in DEFW statements |
| 3.7 | Added support for binary numbers; added support for specifying the base of numeric values in DEFB, DEFM, DEFS and DEFW statements; added the s and S directives and support for DEFS statements with non-zero byte values |
| 3.1.4 | Added support for DEFB and DEFM statements that contain both strings and bytes |
| 2.4 | New |