// C translation of chunk4 ($0200-$25FF): the fixed-point math helpers,
// the instrument needle / pixel-list / message drawing routines and the
// disk block loader. Function names follow the disassembly labels.

#ifndef CHUNK4_H
#define CHUNK4_H

#include <stdbool.h>
#include <stdint.h>

// Math ---------------------------------------------------------------

// AXDiv2: signed halve of a 16-bit value.
uint16_t chunk4AxDiv2(uint16_t ax);
// DivideSigned16 (L16A2): $C2/$C3 = (A:X) / ($C4/$C5); charges 35 work
// units. Returns the quotient (also left in $C2/$C3).
int16_t  chunk4DivideSigned16(uint8_t aHi, uint8_t xLo);
// MultiplyAXByC2: 16x16 unsigned multiply into $C6..$C9; returns the
// middle word ($C7 low, $C8 high) the 6502 leaves in A/X.
uint16_t chunk4MultiplyAXByC2(uint16_t ax);
// MultiplyXY (L1818): signed 7x7 multiply. `carryIn` is the caller's
// carry flag, which becomes bit 0 of the low byte. Returns lo | hi<<8.
uint16_t chunk4MultiplyXY(uint8_t y, uint8_t x, bool carryIn);
// MultiplyXYAndHalve (L180C).
uint16_t chunk4MultiplyXYAndHalve(uint8_t y, uint8_t x);
// NegateAX (L1880).
uint16_t chunk4NegateAX(uint16_t ax);
// ScaleC2ByAX / ScaleC2ByAXIntoC2 / ScaleC2ByC4 / ZPScale.
int16_t  chunk4ScaleC2ByAX(uint16_t ax);
int16_t  chunk4ScaleC2ByAXIntoC2(uint16_t ax);
int16_t  chunk4ScaleC2ByC4(void);
void     chunk4ZpScale(uint8_t xSlot, uint8_t ySlot, uint8_t destSlot);
// SinByteAngle (L1763) and SinShiftedByteAngle (L1768).
int16_t  chunk4SinByteAngle(uint8_t angle);
int16_t  chunk4SinShiftedByteAngle(uint8_t angle);

// Drawing ------------------------------------------------------------

void chunk4ClearViewportsToBlack(void);
void chunk4DrawFuelOrOilGauge(uint8_t xLo, uint8_t y);
void chunk4DrawIndicatorDialNeedle(uint8_t pos, uint8_t index);
// DrawMessage (slew readout with the 5-digit number in $B6/$B7).
void chunk4DrawMessage(uint16_t msg);
void chunk4DrawMessageOrange(uint16_t msg);
void chunk4DrawMessageWhite(uint16_t msg);
void chunk4DrawMultiMessage(uint16_t msg);
// DrawPixelList: PixelListData points at the list; x may exceed 255
// through PixelListXHi.
void chunk4DrawPixelList(uint8_t xLo, uint8_t y);
void chunk4DrawPixelListHelper(uint16_t list, uint8_t xLo, uint8_t y);
// DivideByAXAndSetDigitY: one decimal digit of $B6/$B7 into ($B8),Y.
void chunk4DivideByAXAndSetDigitY(uint16_t divisor, uint8_t digitIndex);

// Instrument updaters (Init entries take the initial value).
void    chunk4UpdateAileronPositionIndicator(uint8_t value);
void    chunk4UpdateAileronPositionIndicatorInit(uint8_t value);
void    chunk4UpdateAirspeedIndicator(void);
void    chunk4UpdateAirspeedIndicatorInit(uint8_t value);
// UpdateAltimeterIndicator's shared table interpolator: returns A and
// leaves the 16-bit result in $C2/$C3.
uint8_t chunk4UpdateAltimeterIndicator(void);
void    chunk4UpdateAltimeterIndicatorInit(void);
void    chunk4UpdateAltimeterIndicatorInit2(void);
void    chunk4UpdateElevatorPositionIndicator(uint8_t value);
void    chunk4UpdateElevatorPositionIndicatorInit(uint8_t value);
void    chunk4UpdateFlapsIndicator(uint8_t value);
void    chunk4UpdateFlapsIndicatorInit(uint8_t value);
void    chunk4UpdateFuelTankGaugesInitLeft(uint8_t value);
void    chunk4UpdateFuelTankGaugesInitRight(uint8_t value);
void    chunk4UpdateFuelTankGaugesLeft(void);
void    chunk4UpdateFuelTankGaugesRight(void);
void    chunk4UpdateFuelTankIndicator(void);
void    chunk4UpdateMixtureControlIndicator(uint8_t value);
void    chunk4UpdateMixtureControlIndicatorInit(uint8_t value);
void    chunk4UpdateOilTempAndPressureGaugesInitPressure(uint8_t value);
void    chunk4UpdateOilTempAndPressureGaugesInitTemp(uint8_t value);
void    chunk4UpdateOilTempAndPressureGaugesPressure(void);
void    chunk4UpdateOilTempAndPressureGaugesTemp(void);
void    chunk4UpdateRudderPositionIndicator(uint8_t value);
void    chunk4UpdateRudderPositionIndicatorInit(uint8_t value);
void    chunk4UpdateSlipSkidIndicator(uint8_t value);
void    chunk4UpdateSlipSkidIndicatorInit(uint8_t value);
void    chunk4UpdateThrottleIndicator(uint8_t value);
void    chunk4UpdateThrottleIndicatorInit(uint8_t value);
void    chunk4UpdateTrimIndicator(uint8_t value);
void    chunk4UpdateTrimIndicatorInit(uint8_t value);
void    chunk4UpdateVerticalSpeedIndicator(void);
void    chunk4UpdateVerticalSpeedIndicatorInit(uint8_t value);

// Disk loader -------------------------------------------------------

// ComputeBlockFromSector: false = carry clear (in range).
bool chunk4ComputeBlockFromSector(void);
void chunk4DoReadBlock(uint8_t blockLo, uint8_t blockHi);
void chunk4DoReadBlockWithStandardDataBuffer(uint8_t blockLo, uint8_t blockHi);
// FetchSectorFromDisk: returns the carry (always clear).
bool chunk4FetchSectorFromDisk(void);
void chunk4PopulateA5ThruA8From1E03(void);
void chunk4ReadBlocks(uint8_t listIndex);
void chunk4SwapFourPagesWithStash(void);
void chunk4SwapPagesWithStash(uint8_t pages);
void chunk4SwapZP(void);

// The seven scenery-loader thunks (SceneryLoaderThunk1..7). In 64K
// mode Apply64KPatchTable routes them to chunk3; the 48K targets are
// not part of the disassembly, so unpatched calls fail (carry set).
bool chunk4SceneryLoaderThunk(int index);
void chunk4SetLoaderPatched(bool patched);

#endif