From 9adc543cc013442ed8d3e491b5779dc0d54237cd Mon Sep 17 00:00:00 2001 From: Chris Pressey Date: Wed, 18 Apr 2018 17:59:42 +0100 Subject: [PATCH] Add TODO note. --- README.md | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/README.md b/README.md index 5d82ede..001a6e7 100644 --- a/README.md +++ b/README.md @@ -75,6 +75,15 @@ TODO To turn `word` type into `byte`. +Trying to remember if we have a compelling case for this or now. The best I can think +of is for implementing 16-bit `cmp` in an efficient way. Maybe we should see if we +can get by with 16-bit `cmp` instead though. + +The problem is that once a byte is extracted, putting it back into a word is awkward. +The address operators have to modify a destination in a special way. That is, when +you say `st a, >word`, you are updating `word` to be `word & $ff | a << 8`, somelike. +Is that consistent with `st`? Well, probably it is, but we have to explain it. + ### Save registers on stack This preserves them, so that, semantically, they can be used later even though they