Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Remove confusing and redundant wording #519

Merged
merged 2 commits into from
Jan 2, 2024
Merged

Remove confusing and redundant wording #519

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
eec0f05
Remove confusing and redundant wording
tobiasvl Dec 14, 2023
144a97b
Link to explanation of interrupt requesting
ISSOtm Jan 2, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 6 additions & 7 deletions src/Interrupt_Sources.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@

## INT $40 — VBlank interrupt

This interrupt is requested every time the Game Boy enters VBlank ([Mode 1](<#PPU modes>)).
This interrupt [is requested] every time the Game Boy enters VBlank ([Mode 1](<#PPU modes>)).

The VBlank interrupt occurs ca. 59.7 times a second on a handheld Game
Boy (DMG or CGB) or Game Boy Player and ca. 61.1 times a second on a
Expand All @@ -20,7 +20,7 @@ The various STAT interrupt sources (modes 0-2 and LYC=LY) have their
state (inactive=low and active=high) logically ORed into a shared
"STAT interrupt line" if their respective enable bit is turned on.

A STAT interrupt will be triggered by a rising edge (transition from
A STAT interrupt [will be triggered][is requested] by a rising edge (transition from
low to high) on the STAT interrupt line.

:::warning STAT blocking
Expand Down Expand Up @@ -52,10 +52,7 @@ hidden by the text box.

## INT $50 — Timer interrupt

Every time that the timer overflows (that is, when [TIMA](<#FF05 — TIMA: Timer counter>) exceeds $FF),
an interrupt is requested by setting bit 2 in the IF register
($FF0F). As soon as that interrupt is enabled, the CPU will execute it by
calling the timer interrupt vector at $0050.
The timer interrupt [is requested] every time that the timer overflows (that is, when [TIMA](<#FF05 — TIMA: Timer counter>) exceeds $FF).

## INT $58 — Serial interrupt

Expand Down Expand Up @@ -98,7 +95,7 @@ clocked serial transfer does not exit STOP mode.

## INT $60 — Joypad interrupt

The Joypad interrupt is requested when any of [`P1`](<#FF00 — P1/JOYP: Joypad>) bits 0-3 change
The Joypad interrupt [is requested] when any of [`P1`](<#FF00 — P1/JOYP: Joypad>) bits 0-3 change
from High to Low. This happens when a button is
pressed (provided that the action/direction buttons are enabled by
bit 5/4, respectively), however, due to switch bounce, one or more High to Low
Expand All @@ -114,3 +111,5 @@ make no difference. The only meaningful purpose of the Joypad
interrupt would be to terminate the STOP (low power) standby state. GBA SP,
because of the different buttons used, seems to not be affected by
switch bounce.

[is requested]: <#FF0F — IF: Interrupt flag>