Add a note on numeric literals

Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/README.md b/README.md
index 53b07d1..01c4847 100644
--- a/README.md
+++ b/README.md
@@ -173,6 +173,24 @@ your editor (and this repository also holds an [.editorconfig](./.editorconfig)
 to help you on this). If your editor doesn't support some of these options, just
 replace it.
 
+# Numeric literals
+
+In 6502 assembly you can express numeric literals in decimal, hexadecimal and
+binary formats. One useful rule I have been developing over the course of
+programming in 6502 assembly is:
+
+1. Prefer the hexadecimal format: debuggers, emulators, ROM dumps, and related
+   tooling will default to this format.
+2. Use the decimal format for simple numbers which can be trivially translated
+   into hexadecimal format, but which are more simple to write this way
+   (e.g. `lda #0`).
+3. Use binary format for bitmap masks, or other arrangements where each bit has
+   been set/unset following a very strict order (e.g. preparing the value for a
+   PPU register). As for masks, it might be quite trivial to mentally parse
+   which bits are set/unset with something like `lda #$81`, but something like
+   `lda #$AC` might take more time to mentally parse than the more explicit `lda
+   #%10101100`.
+
 # Allocation conventions
 
 I am not going to reinvent the wheel here: just stick to the comments on the