diff options
| -rw-r--r-- | src/alf.1 | 26 | ||||
| -rw-r--r-- | src/alf.rst | 26 | ||||
| -rw-r--r-- | src/asmcode.c | 7 | ||||
| -rw-r--r-- | src/io.c | 12 | ||||
| -rw-r--r-- | src/unalf.1 | 8 | ||||
| -rw-r--r-- | src/unalf.rst | 10 |
6 files changed, 55 insertions, 34 deletions
@@ -27,7 +27,7 @@ level margin: \\n[rst2man-indent\\n[rst2man-indent-level]] .\" new: \\n[rst2man-indent\\n[rst2man-indent-level]] .in \\n[rst2man-indent\\n[rst2man-indent-level]]u .. -.TH "ALF" 1 "2025-12-02" "0.3.0" "Urchlay's Atari 8-bit Tools" +.TH "ALF" 1 "2025-12-03" "0.3.0" "Urchlay's Atari 8-bit Tools" .SH NAME alf \- create Atari 8-bit ALF archives .\" RST source for alf(1) man page. Convert with: @@ -121,7 +121,7 @@ Can be given twice for more detail, or 3 times to dump the token tables (\fIlots\fP of output; for debugging only). .TP .B \-V\fP,\fB \-\-version -Show \fBunalf\fP version number and exit. +Show \fBalf\fP version number and exit. .UNINDENT .\" show version number. . @@ -197,12 +197,26 @@ old disk images as \fBUNALF.COM\fP, and \fBLZ.COM\fP is sometimes called \fBALF.COM\fP or \fBALFER.COM\fP\&. I\(aqve used the original names partly out of respect for the original author, and partly to avoid confusion between my \fBalf\fP/\fBunalf\fP and his Atari ones. +.SS Compression Characteristics +.sp +Larger files compress better than smaller ones. Very small files +will get larger when compressed. Files with lots of entropy (random +garbage, files that are already compressed) will also get larger. +.sp +For text files, compression is usually around 45% to 50%, which +is comparable with \fBarc\fP\&. For SAVEd Atari BASIC, the average is +a little worse: 35% to 40%. For executables, it seems to average +around 30%... unless the executables are already compressed (e.g. +self\-decompressing), in which case they\(aqll get bigger when compressed +with \fBalf\fP\&. .SS File Size Limits .sp -\fBalf\fP (and \fBLZ.COM\fP) have a 16MB file size limit. \fBuanlf\fP -actually can\(aqt handle files above about 15MB, if you compress one with -\fBalf\fP\&. Real Atari 8\-bit files are never this large anyway, so it\(aqs -a pathological case. A real Atari would take hours or even days to +\fBalf\fP (and \fBLZ.COM\fP) have a 16MB file size limit. This applies to +both the input file size, and the compressed size (in case of files +that grow when compressed, e.g. random data). +.sp +Real Atari 8\-bit files are never this large anyway, so it\(aqs a +pathological case. A real Atari would take hours or even days to compress/decompress such files, and you\(aqd have to have a hard disk and a DOS capable of handling multi\-megabyte files... .SS Performance diff --git a/src/alf.rst b/src/alf.rst index 267f993..f265697 100644 --- a/src/alf.rst +++ b/src/alf.rst @@ -95,7 +95,7 @@ OPTIONS tables (*lots* of output; for debugging only). -V, --version - Show **unalf** version number and exit. + Show **alf** version number and exit. .. show version number. @@ -175,13 +175,29 @@ old disk images as **UNALF.COM**, and **LZ.COM** is sometimes called out of respect for the original author, and partly to avoid confusion between my **alf**\/**unalf** and his Atari ones. +Compression Characteristics +--------------------------- + +Larger files compress better than smaller ones. Very small files +will get larger when compressed. Files with lots of entropy (random +garbage, files that are already compressed) will also get larger. + +For text files, compression is usually around 45% to 50%, which +is comparable with **arc**. For SAVEd Atari BASIC, the average is +a little worse: 35% to 40%. For executables, it seems to average +around 30%... unless the executables are already compressed (e.g. +self-decompressing), in which case they'll get bigger when compressed +with **alf**. + File Size Limits ---------------- -**alf** (and **LZ.COM**) have a 16MB file size limit. **uanlf** -actually can't handle files above about 15MB, if you compress one with -**alf**. Real Atari 8-bit files are never this large anyway, so it's -a pathological case. A real Atari would take hours or even days to +**alf** (and **LZ.COM**) have a 16MB file size limit. This applies to +both the input file size, and the compressed size (in case of files +that grow when compressed, e.g. random data). + +Real Atari 8-bit files are never this large anyway, so it's a +pathological case. A real Atari would take hours or even days to compress/decompress such files, and you'd have to have a hard disk and a DOS capable of handling multi-megabyte files... diff --git a/src/asmcode.c b/src/asmcode.c index 831ba1c..9cdf2f8 100644 --- a/src/asmcode.c +++ b/src/asmcode.c @@ -252,7 +252,8 @@ L7737: cpy_i(0x88); beq(L7771); // jmp(cleanup_and_exit); - exit(0); + // printf("got here, Y is %d, C is %d\n", Y, CF); + // exit(0); /* was causing early exit with large (5+MB) files */ /* ---------------------------------------------------------------------------- */ L7771: jsr(L79E7); @@ -345,7 +346,7 @@ void L7A19(void) { beq(L7A28); L7A21: jsr(readblock); - Y = 1; /* CIO would set this */ + // Y = 1; /* CIO would set this */ jsr(L7A5D); rts(); L7A28: @@ -369,7 +370,7 @@ L7A40: ora(buf_len_h); beq(L7A57); jsr(readblock); - Y = 1; /* CIO would set this */ + // Y = 1; /* CIO would set this */ L7A57: ldy_i(0x88); jsr(L7A5D); @@ -1,3 +1,4 @@ +// #include <f65.h> #include "unalf.h" #include "addrs.h" @@ -130,6 +131,7 @@ int read_alf_header(void) { /* read buf_len_l/h bytes into buf_adr_l/h, then store the number of bytes actually read in buf_len_l/h. TODO: what about EOF? */ void readblock(void) { + static int bytes_read = 0; int bytes, len, bufadr; u8 *buf; @@ -137,9 +139,15 @@ void readblock(void) { buf = mem + bufadr; len = dpeek(buf_len_l); - // fprintf(stderr, "readblock, bufadr = $%04x, len = $%04x\n", bufadr, len); - bytes = fread(buf, 1, len, in_file); + bytes_read += bytes; + + /* mimic CIO's behaviour */ + if(feof(in_file)) { + ldy_i(0x88); + } else { + ldy_i(1); + } dpoke(buf_len_l, bytes); } diff --git a/src/unalf.1 b/src/unalf.1 index 2c8054f..edcf2b8 100644 --- a/src/unalf.1 +++ b/src/unalf.1 @@ -399,14 +399,6 @@ old disk images as \fBUNALF.COM\fP, and \fBLZ.COM\fP is sometimes called \fBALF.COM\fP or \fBALFER.COM\fP\&. I\(aqve used the original names partly out of respect for the original author, and partly to avoid confusion between my \fBalf\fP/\fBunalf\fP and his Atari ones. -.SH BUGS -.sp -A minor one: \fBunalf\fP can\(aqt correctly extract files larger than about -15MB. This could be a problem in \fBalf\fP (though the archives look -OK to me), or it could be a bug I introduced when porting \fBunalf\fP, -or it could be a bug in the original \fBDZ.COM\fP\&. Files this large are -a pathological case for \fIALF\fP, anyway, since nobody ever used them on -the Atari 8\-bit. .SH COPYRIGHT .sp The original AlfCrunch (\fBDZ.COM\fP and \fBLZ.COM\fP) for the Atari diff --git a/src/unalf.rst b/src/unalf.rst index 069fad1..ed89d2d 100644 --- a/src/unalf.rst +++ b/src/unalf.rst @@ -351,16 +351,6 @@ old disk images as **UNALF.COM**, and **LZ.COM** is sometimes called out of respect for the original author, and partly to avoid confusion between my **alf**\/**unalf** and his Atari ones. -BUGS -==== - -A minor one: **unalf** can't correctly extract files larger than about -15MB. This could be a problem in **alf** (though the archives look -OK to me), or it could be a bug I introduced when porting **unalf**, -or it could be a bug in the original **DZ.COM**. Files this large are -a pathological case for *ALF*, anyway, since nobody ever used them on -the Atari 8-bit. - COPYRIGHT ========= |