Re: A85: holding a mem addr in hl and modifying it via (hl) to save memo

Re: A85: holding a mem addr in hl and modifying it via (hl) to save memory

• To: assembly-85@lists.ticalc.org
• Subject: Re: A85: holding a mem addr in hl and modifying it via (hl) to save memory
• From: mgp4007@omega.uta.edu (Michael Pearce)
• Date: Sat, 02 May 1998 04:43:12 GMT
• Delivered-To: assembly-85-outgoing@towerguard.unix.edu.sollentuna.se
• In-Reply-To: <19980501.213220.10286.0.nine1one@juno.com>
• References: <19980430115407.26939.qmail@hotmail.com> <3548b599.152814402@omega.uta.edu> <19980501.213220.10286.0.nine1one@juno.com>
• Reply-To: assembly-85@lists.ticalc.org

in this code, "ld (hl),a" is loading an 8-bit value into the memory
location, while it seems that both the x and y coordinate are using 2
bytes of storage each, which i assume you don't want.  so if you
already loaded xmem with an address or whatever, only one of these
bytes will be overwritten with ld (hl),a .  maybe that helps, maybe
not.

-mike pearce

>
>ld a, 20		; 20 is the x coord
>ld (hl), a		; load 20 into the memory address of (xmem)
>stored at hl
>inc hl		; since (ymem) proceeds (xmem) in address number
>inc hl
>ld a, 40		; would give me the addr of (ymem) and I could
>load 40 into
>ld (hl), a		; the y position
>ret
>

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• A85: holding a mem addr in hl and modifying it via (hl) to save memory
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