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| author | user <user@clank> | 2026-07-18 22:06:35 +0200 |
|---|---|---|
| committer | user <user@clank> | 2026-07-18 22:06:35 +0200 |
| commit | 4425150cb6f52d15f513690a75645639358a2030 (patch) | |
| tree | b186e048c286f7fb9b78552fb10ebf417ac5178c /src/kdata.asm | |
| parent | term: latch SCY in VBlank - fix ring-scroll shear on live displays (diff) | |
| download | gbos-4425150cb6f52d15f513690a75645639358a2030.tar.gz gbos-4425150cb6f52d15f513690a75645639358a2030.tar.xz gbos-4425150cb6f52d15f513690a75645639358a2030.zip | |
kernel: CGB double-speed mode - 2x everything (1.99x measured)
KEY1 prepare + STOP at KernelInit (skipped on warm reboot if already
fast). The PPU/LCD keep their normal rate; the timer and DIV double
with the CPU, compensated at the two consumers:
- TimerISR now fires at 128 Hz; a toggle byte keeps wTicks at 64 Hz
(uptime semantics unchanged)
- sys_sleep halves the DIV-delta accumulator's high byte (256 DIV
ticks = 1/128 s in double speed) so gsleep/msleep stay real-time
Measured: count 60 (scroll-heavy) 3.77s -> 1.89s wall; wTicks 64 Hz
over 4s; ping's 800ms msleep pacing unchanged (2.77s for 4 echoes).
sl0pboy already emulated KEY1/STOP + per-speed timer/PPU rates.
Diffstat (limited to 'src/kdata.asm')
| -rw-r--r-- | src/kdata.asm | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/src/kdata.asm b/src/kdata.asm index b0cd71b..13dc6dd 100644 --- a/src/kdata.asm +++ b/src/kdata.asm @@ -66,3 +66,5 @@ wBootA:: DS 1 ; A at entry: console model from the boot ROM wBootB:: DS 1 ; B at entry: bit0 set = AGB (GBA in CGB mode) wBootFsFresh::DS 1 ; fs_init formatted a blank disk this boot wTicks:: DS 4 ; monotonic 64 Hz system tick (TimerISR), LE +wTickTog:: DS 1 ; TimerISR fires at 128 Hz in double-speed mode; + ; this toggle keeps wTicks counting at 64 Hz |