battle: matching functions related to battle tick processing/advancement

[GinNoOokami]

This was a fun one. Matched functions that handle tick processing and accumulation, most notably: BattleAdvanceTimers and BattleProcessTimers. The accumulators are double buffered because the producers write from the VSync interrupt handler while the consumers may be in the middle of reading from the main loop. g_BattleTimerBufferIndex does need to be declared volatile to match, and it does make sense why it might have been in this context.

As usual with the core battle mechanics, I've cross referenced these with the FAQ and added comments to help explain what's going on in what is hopefully clear language. I've also added some macros to make the magic numbers for the fixed point accumulators and fractions (which use different precisions), and other bits easier to read.

Despite understanding most of what it does, I still have no idea what to name func_800B0234. Naming is hard. ☹️

Renames:

Functions

• func_800B0170 -> BattleAdvanceTimers
• func_800AFECC -> BattleProcessTimers
• func_800AFE98 -> BattleUnitGetPendingConstTicks
• BattleRecalcUnitSpeed -> BattleUnitCalcSpeed
• BattleApplyRegenPoisonTick -> BattleUnitSetHpChangeRate

Fields

• BattleTurnWork.unitSpeed -> varSpeed
• BattleTurnWork.atbSpeedMultiplier -> constSpeed
• BattleTurnWork.unk6 -> hpChangeRate

Globals

• D_800F499C -> g_BattleTimerBufferIndex
• D_800F49A0 -> g_BattleGlobalTimerAccum
• D_800F49A8 -> g_BattleVarTimerAccum
• D_800F49F8 -> g_BattleConstTimerAccum
• D_800F4A48 -> g_BattleVarTimerFrac
• D_800F4A70 -> g_BattleConstTimerFrac
• D_800F4A98 -> g_BattleHpChangeFrac