diff options
| -rw-r--r-- | 02/README.md | 8 | ||||
| -rw-r--r-- | 02/in01 | 2 | ||||
| -rw-r--r-- | 03/in02 | 404 | ||||
| -rw-r--r-- | 03/in03 | 6 |
4 files changed, 382 insertions, 38 deletions
diff --git a/02/README.md b/02/README.md index 1a77e50..d09c7ca 100644 --- a/02/README.md +++ b/02/README.md @@ -71,6 +71,7 @@ plus six new ones: - `--` outputs a label's (absolute) address - `:-` outputs a label's relative address - `##` outputs a number +- `~~` outputs 255 zeros - `//` is for comments - `\n\n` does nothing (used for spacing) @@ -172,6 +173,13 @@ since `0x90` gets inserted between the "load immediate" instruction code and the `\n\n` works identically, and lets us space out code a bit. But be careful: the number of blank lines must be a multiple of 3! +In the middle of the label table, you'll find a mysterious `ff` byte. This is at the position for +the command `~~` (the end of the command table overlaps with the start of the label table). +This command is just 255 bytes of zeros. If you defined a label whose position in the label +table overlaps with these zeros, you'd screw up the command. But fortunately, this will only happen +if you include `\r` or a non-printing character in your label names. +This is so that you can have big buffers to put data in (like our label table from this compiler). + ## limitations Many of the limitations of our previous compilers apply to this one. Also, @@ -16531,7 +16531,6 @@ unused padding linux doesn't seem to like writing at addresses past the end of the file. so we do have to include this -;cc;cc;cc;cc;cc;cc;cc;cc;cc;cc;cc;cc;cc;cc;cc;cc ;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00 ;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00 ;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00 @@ -16640,6 +16639,7 @@ so we do have to include this ;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00 ;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00 ;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00 +;ff;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00 command ~~ outputs 255 bytes of zeros ;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00 ;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00 ;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00;00 @@ -1,36 +1,6 @@ -jm -:-co -::if -'i -'n -'0 -'3 -00 -::of -'o -'u -'t -'0 -'3 -00 -::BD -'B -'a -'d -20 -'d -'i -'g -'i -'t -\n -// -// -// -::co // open input file im ---if +--IF JA zA IA @@ -39,7 +9,7 @@ im sy // open output file im ---of +--OF JA im ##241. @@ -50,14 +20,145 @@ DA im ##2. sy +// read next line +::rl +im +--LI +RA rbp pointer to line buffer +::rL read loop im -##43. +##3. input file descriptor +JA +IR where to read into +im +##1. +DA read 1 byte +im +##0. syscall 0 (read) +sy +// check how many bytes were read +BA +im +##1. +jg if 1 greater than number of bytes read +:-ef end of file +BR +DR pointer to character we just read +im +##1. ++B +RA +BD +zA +lb +BA +im +##a. +jn +:-rL keep looping +// we now have a full line from the file in ::LI +// the pointer to the end of the line is in rbp +// look at the first character +im +--LI +BA +zA +lb BA im ---hx -cl +##3b. ascii ';' +je if it's a comment, +:-rl jump back to read the next line +im +##a. ascii '\n' +je if it's a blank line, +:-rl jump back to read the next line +im +##3a. ascii ':' +je +:-ld label definition jm :-ex +// label definition +::ld +// first, check if we're on the second pass. +im +--2P +BA +zA +lb +BA +zA +jn if on second pass, +:-rl ignore this (read next line) +// first get current address +im +##4. output fd +JA +zA +IA offset = 0 +im +##1. whence = SEEK_CUR +DA +im +##8. syscall 8 = lseek +sy +BA +im +##400000. address of start of file ++B +DA put current address in rdx +im +--L$ +BA +lq +JA +im +--LI +IA +// copy from rsi to rdi until a newline is reached +::lc label copy +BI +zA +lb +BA +// store in rdi +AJ +xc +sb +CA put byte in rcx +// increment rdi,rsi +BJ +im +##1. ++B +JA +BI +im +##1. ++B +IA +BC +im +##a. +jn if byte we read wasn't a newline, +:-lc keep looping +// store address of label in rdi +AD +BJ +sd +// increment rdi by 4, because we stored an 4-byte number +im +##4. ++B +JA +// now set L$ to rdi +im +--L$ +BA +AJ +sq +cc // // // exit with code in rax @@ -112,3 +213,236 @@ im ##1. jm :-ex +// end of file +::ef +// TODO: second pass +zA exit code 0 +jm +:-ex +::2P second pass? +00 +::IF input file name +'i +'n +'0 +'3 +00 +::OF output file name +'o +'u +'t +'0 +'3 +00 +::BD bad digit error message +'B +'a +'d +20 +'d +'i +'g +'i +'t +\n +::LI line buffer +~~ +::L$ end of current label list +--LB +::LB labels +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ +~~ @@ -1,9 +1,11 @@ -J=d0 +:lbab +;J=d0 + A=d60 syscall :label B+=J B<<=9 B-=J -J?<B-label +J?<B:label |