Bug 182 - ds.X slightly inconsistent behaviour? (discuss!)
Summary: ds.X slightly inconsistent behaviour? (discuss!)
Status: RESOLVED FIXED
Alias: None
Product: RMAC
Classification: Unclassified
Component: Core (show other bugs)
Version: unspecified
Hardware: PC Linux
: Normal enhancement
Assignee: Shamus Hammons
URL:
Depends on:
Blocks:
 
Reported: 2021-03-06 12:18 CST by ggn
Modified: 2022-05-30 12:39 CDT (History)
1 user (show)

See Also:

Attachments
The patches! (1019 bytes, patch)
2021-03-06 12:19 CST, ggn 		Details
View All Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description ggn 2021-03-06 12:18:06 CST 
Consider the following program:

    nop

    dc.w $1000-*
    ds.b $1000-$
    moveq #0,d0

Assembling this, the dc.w will produce what's expected, i.e. subtract 2 from $1000 for a result of $ffe. The ds.b on the other hand will fail with the error "Error: illegal relative address". "Why's that?" I wondered.

Taking a peek at the source, I saw that the implementation of d_ds() makes a call to abs_expr() to calculate the value. This has a clause that makes it fail if the expression is in a TEXT/DATA/BSS segment (which is considered relative). I think this check was there due to ds.X in the past being legal only in the BSS segment, or something close to that.

I think that we can replace that to a plain call to expr() so it can be more flexible.

I'll attach a patch in a bit, let me know if you can think of any reasons why we shouldn't do this!
Comment 1 ggn 2021-03-06 12:19:50 CST 
Created attachment 159 [details]
The patches!
Comment 2 Shamus Hammons 2022-05-30 12:39:42 CDT 
Thanks for the patch!  :-)