CallGraph aggregates history entries whose Source matches the supplied filter into (From → To) edges, sorted by descending count. Ties broken by (From

Dispatch is the unconditional RST $08 trap runner. Equivalent to HookFunc's callback but skips the divMMC-signature gate. Tests use this to drive the

EnableDisciple enables the DISCiPLE disk interface with auto-paging hooks on the CPU. The DISCiPLE starts paged out (safe for mid-session enable). Use

EnableDisciple enables the Disciple disk interface

GetRAM returns the 8KB RAM.

HasMoreBlocks returns true if at least one more block is available.

Intrq reports the interrupt-request line (set at command completion).

IsBetaActive reports whether the TR-DOS ROM is currently paged over the system ROM.

IsRedButtonPressed returns whether the red button is pressed

IsZXPrinterEnabled reports whether the printer is attached.

Register read-backs. VMPR reads OR in the RXMIDI status bit; the others read back the stored value.

LoadDisk parses a disk image (DSK / EDSK / UDI / MGT / IMG / TRD) and attaches it to the given physical drive (0 = A, 1 = B). Replaces any previously-

LoadROMsForModel loads all ROMs required for a specific Spectrum model

New returns a zero-initialised keymap.

NewDefault builds a SAM machine from the bundled ROM 3.0.

PreFetchHook is the callback the Z80 should invoke before each opcode fetch. Pages the IF1 ROM IN when PC matches one of the page-in triggers. The che

Push appends an entry, overwriting the oldest if the ring is full. Hot path — keep allocations to zero.

RestartAll calls restart() on every drive. The IF1 ULA does this after every CTR or NET port access — once the host has finished a command, the drives

SelectChip sets the active TurboSound chip (0..2), clamping higher values. Driven by the $FFFD chip-select protocol (write 0xFF/0xFE/0xFD to select ch

SelectSlot applies a port $303B write: sets the current sprite and the pattern-RAM upload cursor (ports.txt 0x303B).

SetDataAt writes the raw byte at the given absolute offset.

SetResolution installs the NR$70 resolution (0 = 256×192, 1 = 320×256, 2 = 640×256). Higher bits are ignored.

SetRom3Query installs the predicate that reports whether ROM3 is the currently-selected machine ROM. rom3 entry points engage automap only when it ret

WireLineInterrupt installs NR$22 / NR$23 OnWrite handlers so the guest can program a per-frame "line interrupt" — a second INT pulse asserted when the

Write8 stores an 8-bit palette value (NextReg 0x41 write behaviour: high 8 of 9 bits, low blue bit forced to 0) at the current index, then advances th

WriteAddrLow handles a write to NextReg $29 — addr[7:0].

WriteNR44 implements the NextReg 0x44 two-byte protocol against the Bank's internal latch (pending9/have9). The first call stashes val and arms the la

applySnapshotToEmulator applies a loaded snapshot to the running emulator.

buildZ80V2V3 assembles a minimal v2/v3 file (one compressed bank) and returns the loaded snapshot. addlLen selects the version (23=v2, 54/55=v3); hwMo

cmdBankPeek parses `bank-peek KIND BANK OFF [LEN]` and returns either a hexdump line or an ERR.

cmdContUntil arms a one-shot conditional-continue. The CPU resumes (or stays running if it was already running) until the expression evaluates true at

cmdSetReg writes a CPU register. Accepts 8-bit (A/B/C/D/E/H/L/F/I/R) or 16-bit (AF/BC/DE/HL/IX/IY/SP/PC) register names — case-insensitive. Used by lo

currentROMBank returns the bank index (0-3) currently mapped at $0000-$3FFF. Used for bank-filtered breakpoints.

generateBeeperFrame synthesises one frame's worth of mono beeper samples from a list of speaker-toggle events. Returns the samples and the speaker sta

rawDirent builds one 32-byte 8.3 directory entry. name11 must be the 11-byte padded form.

syncMMUFromPage updates the two 8K MMU slots that correspond to the given 16K page slot (0..3) from the current memoryPageReadMap, and clears mmuOverr

ULA setter/getter coverage: SetTapePlayer + GetTapePlayer, Reset clears border/mic/speaker/AY state, SetPeripherals nil-safe, SetNextDMA / Compositor

ActiveVideoLine returns the current raster line within the frame, derived from the CPU's T-state position (T-states since frame start / T-states-per-l

Add inserts or replaces a watch keyed by Reg.

AdvanceMotor rotates the motor-on bit through the daisy chain. Called by the IF1 ULA when it sees a falling edge on the comms clock with comms-data lo

AssertSandboxed fails the test if install.Path() resolves to somewhere outside a temp directory. Call this from test fixtures that are about to write

BetaPreFetch advances the Beta Disk auto-paging state machine for an instruction fetch at pc. Call it from the CPU's pre-fetch hook so the byte fetche

Bytes returns the underlying image data. Tests and callers that want to inspect contents (e.g. for verifying a NextZXOS write landed at the right LBA)

Clock advances one i_CLK rising edge and returns o_Tx for this cycle. VHDL register ordering reproduced (all sampled off the SAME clock edge): - fall

Close closes the audio system and releases resources.

EnableZXPrinter attaches a ZX Printer to the peripheral bus. Prints accumulate in a bitmap buffer the caller can access via ZXPrinter() → Bitmap()/Sav

EncodeSnapshot wraps a snapshot.Snapshot in an RZX SnapshotBlock by asking the snapshot package to serialise itself in the requested format. The on-th

FPGABootROMActive reports whether the bootrom is currently masking the low ROM area. Exposed for debug snapshots and tests.

HandlePortRead handles IN (0xFB). Returns the current drum / stylus status bits the ROM polls for. The port decode is loose — any port with bit 2 clea

InsertDisk loads a disk; Eject removes it.

Instructions returns the instruction count the CPU should execute during the current frame. The driver passes this to CPU.ExecuteRZXFrame. Mirrors lib

IsBreakPressed returns whether the BREAK key is currently pressed

NewHistory returns a History sized to hold size entries. size <= 0 disables recording (Push is a no-op).

Read parses a .mdr byte slice into a fresh Cartridge. The buffer length must be a whole number of blocks (10..254) optionally plus one trailing byte f

ReadStatusPort returns the AND of all drives' status bits, plus the caller-supplied bus-wide bits (DTR, BUSY) ORed in by the ULA. Mirrors the drive lo

Refresh re-pulls the ring and updates labels.

Save saves a snapshot to a file.

Select applies a NextReg 0x06 ("Peripheral 2") write. Per the FPGA spec, bits 1-0 are the AUDIO CHIP MODE (00 = YM, 01 = AY, 10 = ZXN-8950, 11 = hold

SetActive selects which palette (first=0, second=1) the given layer uses for rendering. Only the low bit of which is honoured. This lets render code u

SetFPGABootROM installs the Spectrum Next FPGA bootrom image and enables bootrom mode. While active, reads at $0000-$3FFF come from the supplied 8 KB

SetLayer2MapControl applies a write to the legacy Layer-2 port $123B (zxnext.vhd:3915-3922). Bit 4 clear configures the map (bit0=write-enable, bit1=v

SetMode40 is a convenience for tests: clears the 80-col bit.

SetNow installs a time provider — useful for tests that need a deterministic clock. Pass nil to revert to time.Now().

SetRZXPlaybackHook installs (or removes, with hook=nil) the RZX playback IN-byte source. The hook returns ok=true with the next recorded byte, or ok=f

SetSide chooses the active head (0 or 1).

SetSpeedlockEnabled turns the Speedlock copy-protection workaround on or off. When enabled, repeated READ DATA commands on the same sector return prog

SetTracer installs a per-access callback. Pass nil to disable. The callback fires AFTER the access — the value parameter is the value that was written

SetTstates overrides the T-state counter. Used by RZX playback to align timing with the recorded T-state offset before resuming the CPU from a snapsho

TypeRune overlays the SAM key combination for the typed host symbol r as a brief pulse, independent of the host keyboard layout. Returns true if r is

WireMachineType installs the NextReg $03 OnWrite handler for the config-mode bookkeeping side of machine-type selection. Real hardware (per TBBlue FPG

WriteAddrHigh handles a write to NextReg $28. Bit 7 selects joymap, bit 0 is the high bit (addr[8]) of the address.

ZXPrinter returns the attached printer or nil. Used by the UI for Save / Clear menu actions.

addSymbol adds or updates a single symbol-table entry. Used by the runtime `sym $ADDR NAME` debugger command so users can name addresses they've ident

blankMGT builds an empty 800K MGT disk (used by tests and formatting).

checkSDCommand is fed from the SD card's command logger on every command the card receives (it carries the live cpu.PC). When an armed `break-on-sd` s

cmdNRTrace adds NextReg numbers to the live trace set, lists the current set, or clears it. nr-trace list active nr-trace REG[,REG…] add

cmdProvenance arms/disarms the tracer or queries one address. provenance show armed state provenance on arm (start recor

fakeROM returns an 8KB ROM image where each byte is the low 8 bits of its address. Lets the tests confirm a specific byte came from the IF1 ROM rather

idAt walks the track byte stream from position start, looking for an IDAM (sync mark + 0xFE with clock). Returns (cylinder, head, sector, size, idEndP

mmuTestROMs lays down minimal ROM blobs so memory.New succeeds for whatever model the caller asks for. Identical content to the existing tests but pri

newCrashDetector returns nil when cfg disables every heuristic so callers can skip installing the hook entirely.

divMMC state-transition matrix — the cross-product of automap × CONMEM × entry-point-gate × page-out trigger, driven as full transition sequences. The

newTraceDB allocates a ring of the given capacity. A non-positive capacity yields nil (disabled).

onExecute marks an instruction boundary (wire to AddPreFetchHook). It counts executions of startPC and arms once the startHit-th is seen.

onRead records one RAM read (wire to SetRAMReadHook). bank16k is the physical 16K bank, off the byte offset within it, val the byte read.