PATH: Fix b(field) Fcode evaluation - OpenBIOS

25 May 2009

Hi everyone,

This patch fixes the Fcode evaluation of b(field) which was implemented 
incorrectly. With this patch applied, corruption seen in several of the 
package words for Milax/Martux has now disappeared. Included below are 
the Fcode test cases I used (courtesy of Milax):

\ Test Fcode struct...field...constant (no headers)
\ Forth: struct /x field >filesize /x field >offset /x field >block0 
constant /file-record 0 >offset .
here
cc c,				\ offset16
a5 c,				\ 0
02 c, 48 c,			\ /x
b5 c, 08 c, 00 c, 		\ new-token
be c,				\ b(field)
02 c, 48 c, 			\ /x
b5 c, 08 c, 01 c, 		\ new-token
be c, 				\ b(field)
02 c, 48 c,			\ /x
b5 c, 08 c, 02 c, 		\ new-token
be c, 				\ b(field)
b5 c, 08 c, 03 c,		\ new-token
ba c,				\ b(constant)
a5 c,				\ 0
08 c, 01 c,			\ Fcode #801
9d c,				\ Display stack
00 c,				\ End

\ Headers version
here
cc c,											\ offset16
a5 c,											\ 0
02 c, 48 c, 										\ /x
b6 c, 09 c, 3e c, 66 c, 69 c, 6c c, 65 c, 73 c, 69 c, 7a c, 65 c, 			\ 
named-token (>filesize)
08 c, 00 c,										
be c,											\ b(field)
02 c, 48 c,										\ /x
b6 c, 07 c, 3e c, 6f c, 66 c, 66 c, 73 c, 65 c, 74 c, 					\ named-token 
(>offset)
08 c, 01 c, 								
be c,											\ b(field)
02 c, 48 c,										\ /x
b6 c, 07 c, 3e c, 62 c, 6c c, 6f c, 63 c, 6b c, 30 c,					\ named-token 
(>block0)
08 c, 02 c,
be c, 											\ b(field)
b6 c, 0c c, 2f c, 66 c, 69 c, 6c c, 65 c, 2d c, 72 c, 65 c, 63 c, 6f 
c, 		\ named-token (/file-record)
       72 c, 64 c,
08 c, 03 c,
ba c, 											\ b(constant)
a5 c,											\ 0
08 c, 01 c, 										\ Fcode #801
9d c,											\ Display stack
00 c,											\ End

ATB,

Mark.

-- 
Mark Cave-Ayland - Senior Technical Architect
PostgreSQL - PostGIS
Sirius Corporation plc - control through freedom
http://www.siriusit.co.uk
t: +44 870 608 0063