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authorAstrid Smith2011-06-24 23:52:23 -0700
committerAstrid Smith2011-06-25 01:23:51 -0700
commit9d760f5d76cc5201b0b5f3bed355670dd1f7fac1 (patch)
tree110d8239acec00ce79e1ddf336e5f73b2a340ad6 /README.markdown
parent8180013ecccbb1eff2ff3f93621309225a285dba (diff)
Make JR ignore page boundaries; relative jumps are now twenty times as fast.
Diffstat (limited to 'README.markdown')
-rw-r--r--README.markdown10
1 files changed, 9 insertions, 1 deletions
diff --git a/README.markdown b/README.markdown
index 2c39862..7f1c6b5 100644
--- a/README.markdown
+++ b/README.markdown
@@ -44,7 +44,7 @@ instruction with a fixed 42 cycle overhead:
(Using techniques borrowed from
[Tezxas](http://tezxas.ticalc.org/technica.htm) I will be able to get
-this to 30 cycles.)
+this to 26 cycles.)
From there, an instruction will take anywhere from 0 to, well, lots of
additional cycles. Generally, however, it will take under 50, for 92
@@ -66,3 +66,11 @@ expected.
* [More z80 instruction set reference](http://nemesis.lonestar.org/computers/tandy/software/apps/m4/qd/opcodes.html)
* [Details on flags and other side effects](http://www.gaby.de/z80/z80code.htm)
+Incompatibilities with Real Hardware
+------------------------------------
+
+1. PC-relative accesses (reads, writes, jumps) across page boundaries
+ may not work. This is apparently a rare enough occurence that
+ ignoring it is reasonable.
+
+2.