From: cinap_lenrek@felloff.net
To: 9front@9front.org
Subject: Re: [9front] Re: [PATCH] game boy advance header target for 5l
Date: Sat, 04 Mar 2023 16:53:53 +0100 [thread overview]
Message-ID: <B8CCBA61902779C56B8247511AC8EF99@felloff.net> (raw)
In-Reply-To: <cc0b0481-8a24-3025-8fa3-7153a4207e55@posixcafe.org>
> In porting a more complicated rom, I realized that plan9 specific
> init code is unavoidable anyway due to needing to setup R12:
> MOVW $setR12(SB), R12 /* load the SB */
It is not plan9 specific really. It is just an address bias value
for accessing the data section; generated by the linker.
The idea is that you want to keep the offsets small becuse small
offsets are more likely be encodable directly into a single
instruction, while larger ones need multiple instructions.
Also note this is a RISC thing; where you have usually a large
number of general purpose registers. For 386 code, there is
no such thing.
--
cinap
prev parent reply other threads:[~2023-03-04 15:55 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-02 6:56 [9front] " Jacob Moody
2023-03-02 11:15 ` [9front] " Anthony Martin
2023-03-02 16:08 ` Jacob Moody
2023-03-02 17:33 ` cinap_lenrek
2023-03-02 17:50 ` Jacob Moody
2023-03-03 20:59 ` cinap_lenrek
2023-03-03 21:18 ` Jacob Moody
2023-03-04 15:53 ` cinap_lenrek [this message]
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