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author | Rodney W. Grimes <rgrimes@FreeBSD.org> | 1994-05-27 12:33:43 +0000 |
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committer | Rodney W. Grimes <rgrimes@FreeBSD.org> | 1994-05-27 12:33:43 +0000 |
commit | 9b50d9027575220cb6dd09b3e62f03f511e908b8 (patch) | |
tree | defc987843071f19a5891a97145437d43cba2af8 /usr.bin/yacc/NOTES | |
parent | efd31c5952bb9bb2485c109382100127424f8611 (diff) | |
download | src-9b50d9027575220cb6dd09b3e62f03f511e908b8.tar.gz src-9b50d9027575220cb6dd09b3e62f03f511e908b8.zip |
BSD 4.4 Lite Usr.bin Sources
Notes
Notes:
svn path=/cvs2svn/branches/CHRISTOS/; revision=1590
Diffstat (limited to 'usr.bin/yacc/NOTES')
-rw-r--r-- | usr.bin/yacc/NOTES | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/usr.bin/yacc/NOTES b/usr.bin/yacc/NOTES new file mode 100644 index 000000000000..9db3c96ce1b8 --- /dev/null +++ b/usr.bin/yacc/NOTES @@ -0,0 +1,9 @@ +Berkeley Yacc reflects its origins. The reason so many routines +use exactly six register variables is that Berkeley Yacc was +developed on a VAX using PCC. PCC placed at most six variables +in registers. I went to considerable effort to find which six +variables most belonged in registers. Changes in machines and +compilers make that effort worthless, perhaps even harmful. + +The code contains many instances where address calculations are +performed in particular ways to optimize the code for the VAX. |