Divide a by 8

1 files changed, 12 insertions, 2 deletions

diff --git a/Optimizing-assembly-code.md b/Optimizing-assembly-code.md
index 2c308b7..54af5ba 100644
--- a/Optimizing-assembly-code.md
+++ b/Optimizing-assembly-code.md
@@ -22,7 +22,7 @@ WikiTI's advice fully applies here:
   - [Rotate the bits of `a`](#rotate-the-bits-of-a)
   - [Set `a` to some constant minus `a`](#set-a-to-some-constant-minus-a)
   - [Set `a` to one constant or another depending on the carry flag](#set-a-to-one-constant-or-another-depending-on-the-carry-flag)
-  - [Shift `a` right by 3 bits](#shift-a-right-by-3-bits)
+  - [Divide `a` by 8 (shift `a` right 3 bits)](#divide-a-by-8-shift-a-right-3-bits)
   - [Set `a` to some value plus carry](#set-a-to-some-value-plus-carry)
   - [Load from HRAM to `a` or from `a` to HRAM](#load-from-hram-to-a-or-from-a-to-hram)
 - [16-bit registers](#16-bit-registers)
@@ -298,11 +298,21 @@ If `CVAL` is 0 and `NCVAL` is 1 (i.e. set `a` to 0 if carry, or 1 if not carry),
 ```
 
 
-### Shift `a` right by 3 bits
+### Divide `a` by 8 (shift `a` right 3 bits)
 
 Don't do:
 
 ```asm
+	; 6 bytes, 9 cycles
+	; (15 bytes, at least 21 cycles, counting the definition of SimpleDivide)
+	ld c, 8 ; divisor
+	call SimpleDivide
+	ld a, b ; quotient
+```
+
+And don't do:
+
+```asm
 	; 6 bytes, 6 cycles
 	srl a
 	srl a