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Bulk multibyte #4626

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90ea8ac
Remove incorrect and relax unnecessary restrictions on bulk reads in …
SuuperW Apr 18, 2026
04d40ab
Expose multi-byte reads and writes.
SuuperW Dec 14, 2025
d284f26
add tests for new API methods
SuuperW Apr 18, 2026
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80 changes: 74 additions & 6 deletions src/BizHawk.Client.Common/Api/Classes/MemoryApi.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -264,7 +264,7 @@ public IReadOnlyList<byte> ReadByteRange(long addr, int length, string domain =
return newBytes;
}

public void WriteByteRange(long addr, IReadOnlyList<byte> memoryblock, string domain = null)
public void WriteByteRange(long addr, Span<byte> memoryblock, string domain = null)
{
var d = NamedDomainOrCurrent(domain);
if (!d.Writable)
Expand All @@ -273,15 +273,83 @@ public void WriteByteRange(long addr, IReadOnlyList<byte> memoryblock, string do
return;
}
if (addr < 0) LogCallback($"Warning: Attempted writes on addresses {addr}..-1 outside range of domain {d.Name} in {nameof(WriteByteRange)}()");
var lastReqAddr = addr + memoryblock.Count - 1;
var indexAfterLast = Math.Min(Math.Max(-1L, lastReqAddr), d.Size - 1L) + 1L;
var iDst = Math.Min(Math.Max(0L, addr), d.Size);
var iSrc = checked((int) (iDst - addr));
using (d.EnterExit())
var lastReqAddrExclusive = addr + memoryblock.Length;
var lastAddressExclusive = Math.Min(Math.Max(0, lastReqAddrExclusive), d.Size);
var length = lastAddressExclusive - iDst;
if (length > 0) using (d.EnterExit()) d.BulkPokeByte(iDst, memoryblock.Slice(start: iSrc, length: (int)length));
if (lastReqAddrExclusive > d.Size) LogCallback($"Warning: Attempted writes on addresses {d.Size}..{lastReqAddrExclusive} outside range of domain {d.Name} in {nameof(WriteByteRange)}()");
}

public IReadOnlyList<ushort> ReadU16Range(long addr, int count, string domain = null)
{
var d = NamedDomainOrCurrent(domain);
if (addr < 0) LogCallback($"Warning: Attempted reads on addresses {addr}..-1 outside range of domain {d.Name} in {nameof(ReadU16Range)}()");
var lastReqAddr = addr + count * sizeof(ushort) - 1;
var indexAfterLast = Math.Min(Math.Max(-1L, lastReqAddr), d.Size - 1L) + 1L;
var iSrc = Math.Min(Math.Max(0L, addr), d.Size);
var iDst = (iSrc - addr) / sizeof(ushort);
var values = new ushort[(indexAfterLast - iSrc) / sizeof(ushort)];
if (iSrc < indexAfterLast) using (d.EnterExit()) d.BulkPeekUshort(iSrc.RangeToExclusive(indexAfterLast), _isBigEndian, values);
if (lastReqAddr >= d.Size) LogCallback($"Warning: Attempted reads on addresses {d.Size}..{lastReqAddr} outside range of domain {d.Name} in {nameof(ReadU16Range)}()");
if (values.Length == count) return values;
var newValues = new ushort[count];
if (values.Length is not 0) Array.Copy(sourceArray: values, sourceIndex: 0, destinationArray: newValues, destinationIndex: iDst, length: values.Length);
return newValues;
}

public void WriteU16Range(long addr, Span<ushort> memoryblock, string domain = null)
{
var d = NamedDomainOrCurrent(domain);
if (!d.Writable)
{
LogCallback($"Error: the domain {d.Name} is not writable");
return;
}
if (addr < 0) LogCallback($"Warning: Attempted writes on addresses {addr}..-1 outside range of domain {d.Name} in {nameof(WriteU16Range)}()");
var iDst = Math.Min(Math.Max(0L, addr), d.Size);
var iSrc = checked((int) (iDst - addr)) / sizeof(ushort);
var lastReqAddrExclusive = addr + memoryblock.Length * sizeof(ushort);
var lastAddressExclusive = Math.Min(Math.Max(0, lastReqAddrExclusive), d.Size);
var length = lastAddressExclusive - iDst;
if (length > 0) using (d.EnterExit()) d.BulkPokeUshort(iDst, _isBigEndian, memoryblock.Slice(start: iSrc, length: (int)(length / sizeof(ushort))));
if (lastReqAddrExclusive >= d.Size) LogCallback($"Warning: Attempted writes on addresses {d.Size}..{lastReqAddrExclusive} outside range of domain {d.Name} in {nameof(WriteU16Range)}()");
}

public IReadOnlyList<uint> ReadU32Range(long addr, int count, string domain = null)
{
var d = NamedDomainOrCurrent(domain);
if (addr < 0) LogCallback($"Warning: Attempted reads on addresses {addr}..-1 outside range of domain {d.Name} in {nameof(ReadU32Range)}()");
var lastReqAddr = addr + count * sizeof(uint) - 1;
var indexAfterLast = Math.Min(Math.Max(-1L, lastReqAddr), d.Size - 1L) + 1L;
var iSrc = Math.Min(Math.Max(0L, addr), d.Size);
var iDst = (iSrc - addr) / sizeof(uint);
var values = new uint[(indexAfterLast - iSrc) / sizeof(uint)];
if (iSrc < indexAfterLast) using (d.EnterExit()) d.BulkPeekUint(iSrc.RangeToExclusive(indexAfterLast), _isBigEndian, values);
if (lastReqAddr >= d.Size) LogCallback($"Warning: Attempted reads on addresses {d.Size}..{lastReqAddr} outside range of domain {d.Name} in {nameof(ReadU32Range)}()");
if (values.Length == count) return values;
var newValues = new uint[count];
if (values.Length is not 0) Array.Copy(sourceArray: values, sourceIndex: 0, destinationArray: newValues, destinationIndex: iDst, length: values.Length);
return newValues;
}

public void WriteU32Range(long addr, Span<uint> memoryblock, string domain = null)
{
var d = NamedDomainOrCurrent(domain);
if (!d.Writable)
{
while (iDst < indexAfterLast) d.PokeByte(iDst++, memoryblock[iSrc++]);
LogCallback($"Error: the domain {d.Name} is not writable");
return;
}
if (lastReqAddr >= d.Size) LogCallback($"Warning: Attempted writes on addresses {d.Size}..{lastReqAddr} outside range of domain {d.Name} in {nameof(WriteByteRange)}()");
if (addr < 0) LogCallback($"Warning: Attempted writes on addresses {addr}..-1 outside range of domain {d.Name} in {nameof(WriteU32Range)}()");
var iDst = Math.Min(Math.Max(0L, addr), d.Size);
var iSrc = checked((int) (iDst - addr)) / sizeof(uint);
var lastReqAddrExclusive = addr + memoryblock.Length * sizeof(uint);
var lastAddressExclusive = Math.Min(Math.Max(0, lastReqAddrExclusive), d.Size);
var length = lastAddressExclusive - iDst;
if (length > 0) using (d.EnterExit()) d.BulkPokeUint(iDst, _isBigEndian, memoryblock.Slice(start: iSrc, length: (int)(length / sizeof(uint))));
if (lastReqAddrExclusive >= d.Size) LogCallback($"Warning: Attempted writes on addresses {d.Size}..{lastReqAddrExclusive} outside range of domain {d.Name} in {nameof(WriteU32Range)}()");
}

public float ReadFloat(long addr, string domain = null)
Expand Down
7 changes: 6 additions & 1 deletion src/BizHawk.Client.Common/Api/Interfaces/IMemoryApi.cs
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Expand Up @@ -30,9 +30,14 @@ public interface IMemoryApi : IExternalApi
uint ReadU32(long addr, string domain = null);

void WriteByte(long addr, uint value, string domain = null);
void WriteByteRange(long addr, IReadOnlyList<byte> memoryblock, string domain = null);
void WriteByteRange(long addr, Span<byte> memoryblock, string domain = null);
void WriteFloat(long addr, float value, string domain = null);

IReadOnlyList<ushort> ReadU16Range(long addr, int count, string domain = null);
IReadOnlyList<uint> ReadU32Range(long addr, int count, string domain = null);
void WriteU16Range(long addr, Span<ushort> memoryblock, string domain = null);
void WriteU32Range(long addr, Span<uint> memoryblock, string domain = null);
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@YoshiRulz YoshiRulz Feb 22, 2026

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Write*Range signatures are fine for Span, but then why do Read*Range allocate and return arrays?
See also #3472.
Not that you need these anyway, since the caller can just MemoryMarshal.Cast to/from byte.

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@SuuperW SuuperW Feb 22, 2026

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I think it was just a lot simpler to do it that way, and the byte one returns an array IIRC so I was following that.
I knew you were wanting to update some of this stuff anyway, so I didn't think it very important.

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@SuuperW SuuperW Apr 18, 2026

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Update on this: The new read methods return IReadOnlyList, so as to match the existing ReadByteRange method. I considered changing them all to accept a Span instead but that's too much work to do before release.
The existing WriteByteRange method was changed to accept a Span though, since this is good and easy to do and makes it match the new ones.


void WriteS8(long addr, int value, string domain = null);
void WriteS16(long addr, int value, string domain = null);
void WriteS24(long addr, int value, string domain = null);
Expand Down
66 changes: 65 additions & 1 deletion src/BizHawk.Client.Common/lua/CommonLibs/MemoryLuaLibrary.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -120,7 +120,7 @@ public void WriteByteRange([LuaZeroIndexed] LuaTable memoryblock, string domain
[LuaMethodExample("memory.write_bytes_as_array(0x100, { 0xAB, 0x12, 0xCD, 0x34 });")]
[LuaMethod("write_bytes_as_array", "Writes sequential bytes starting at addr.")]
public void WriteBytesAsArray(long addr, LuaTable bytes, string domain = null)
=> APIs.Memory.WriteByteRange(addr, _th.EnumerateValues<long>(bytes).Select(l => (byte) l).ToList(), domain);
=> APIs.Memory.WriteByteRange(addr, _th.EnumerateValues<long>(bytes).Select(l => (byte) l).ToArray(), domain);

[LuaMethodExample("memory.write_bytes_as_dict({ [0x100] = 0xAB, [0x104] = 0xCD, [0x106] = 0x12, [0x107] = 0x34, [0x108] = 0xEF });")]
[LuaMethod("write_bytes_as_dict", "Writes bytes at arbitrary addresses (the keys of the given table are the addresses, relative to the start of the domain).")]
Expand All @@ -132,6 +132,70 @@ public void WriteBytesAsDict([LuaZeroIndexed] LuaTable addrMap, string domain =
}
}

[LuaMethodExample("local values = memory.read_u16_le_as_array(0x100, 30, \"WRAM\");")]
[LuaMethod("read_u16_le_as_array", "Reads count 16-bit values starting at addr into an array-like table (1-indexed).")]
public LuaTable ReadUshortsAsArray(long addr, int count, string domain = null)
{
APIs.Memory.SetBigEndian(false);
return _th.ListToTable(APIs.Memory.ReadU16Range(addr, count, domain));
}

[LuaMethodExample("memory.write_u16_le_as_array(0x100, { 0xABCD, 0x1234 });")]
[LuaMethod("write_u16_le_as_array", "Writes sequential 16-byte values starting at addr.")]
public void WriteUshortsAsArray(long addr, LuaTable values, string domain = null)
{
APIs.Memory.SetBigEndian(false);
APIs.Memory.WriteU16Range(addr, _th.EnumerateValues<long>(values).Select(l => (ushort) l).ToArray(), domain);
}

[LuaMethodExample("local values = memory.read_u16_be_as_array(0x100, 30, \"WRAM\");")]
[LuaMethod("read_u16_be_as_array", "Reads count 16-bit values starting at addr into an array-like table (1-indexed).")]
public LuaTable ReadUshortsBigAsArray(long addr, int count, string domain = null)
{
APIs.Memory.SetBigEndian(true);
return _th.ListToTable(APIs.Memory.ReadU16Range(addr, count, domain));
}

[LuaMethodExample("memory.write_u16_be_as_array(0x100, { 0xABCD, 0x1234 });")]
[LuaMethod("write_u16_be_as_array", "Writes sequential 16-byte values starting at addr.")]
public void WriteUshortsAsBigArray(long addr, LuaTable values, string domain = null)
{
APIs.Memory.SetBigEndian(true);
APIs.Memory.WriteU16Range(addr, _th.EnumerateValues<long>(values).Select(l => (ushort) l).ToArray(), domain);
}

[LuaMethodExample("local values = memory.read_u32_le_as_array(0x100, 30, \"WRAM\");")]
[LuaMethod("read_u32_le_as_array", "Reads count 32-bit values starting at addr into an array-like table (1-indexed).")]
public LuaTable ReadUintsAsArray(long addr, int count, string domain = null)
{
APIs.Memory.SetBigEndian(false);
return _th.ListToTable(APIs.Memory.ReadU32Range(addr, count, domain));
}

[LuaMethodExample("memory.write_u32_le_as_array(0x100, { 0xABCD, 0x1234 });")]
[LuaMethod("write_u32_le_as_array", "Writes sequential 32-byte values starting at addr.")]
public void WriteUintsAsArray(long addr, LuaTable values, string domain = null)
{
APIs.Memory.SetBigEndian(false);
APIs.Memory.WriteU32Range(addr, _th.EnumerateValues<long>(values).Select(l => (uint) l).ToArray(), domain);
}

[LuaMethodExample("local values = memory.read_u32_be_as_array(0x100, 30, \"WRAM\");")]
[LuaMethod("read_u32_be_as_array", "Reads count 32-bit values starting at addr into an array-like table (1-indexed).")]
public LuaTable ReadUintsBigAsArray(long addr, int count, string domain = null)
{
APIs.Memory.SetBigEndian(true);
return _th.ListToTable(APIs.Memory.ReadU32Range(addr, count, domain));
}

[LuaMethodExample("memory.write_u32_be_as_array(0x100, { 0xABCD, 0x1234 });")]
[LuaMethod("write_u32_be_as_array", "Writes sequential 32-byte values starting at addr.")]
public void WriteUintsBigAsArray(long addr, LuaTable values, string domain = null)
{
APIs.Memory.SetBigEndian(true);
APIs.Memory.WriteU32Range(addr, _th.EnumerateValues<long>(values).Select(l => (uint) l).ToArray(), domain);
}

[LuaMethodExample("""
memory.write_bytes_as_binary_string(0x100, string.pack("<i4f", 1234, 456.789), "WRAM")
memory.write_bytes_as_binary_string(0x108, "\xFE\xED", "WRAM")
Expand Down
2 changes: 1 addition & 1 deletion src/BizHawk.Client.Common/lua/LuaHelperLibs/MainMemoryLuaLibrary.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -119,7 +119,7 @@ public void WriteByteRange([LuaZeroIndexed] LuaTable memoryblock)
[LuaMethodExample("mainmemory.write_bytes_as_array(0x100, { 0xAB, 0x12, 0xCD, 0x34 });")]
[LuaMethod("write_bytes_as_array", "Writes sequential bytes starting at addr.")]
public void WriteBytesAsArray(long addr, LuaTable bytes)
=> APIs.Memory.WriteByteRange(addr, _th.EnumerateValues<long>(bytes).Select(l => (byte) l).ToList(), MainMemName);
=> APIs.Memory.WriteByteRange(addr, _th.EnumerateValues<long>(bytes).Select(l => (byte) l).ToArray(), MainMemName);

[LuaMethodExample("mainmemory.write_bytes_as_dict({ [0x100] = 0xAB, [0x104] = 0xCD, [0x106] = 0x12, [0x107] = 0x34, [0x108] = 0xEF });")]
[LuaMethod("write_bytes_as_dict", "Writes bytes at arbitrary addresses (the keys of the given table are the addresses, relative to the start of the main memory).")]
Expand Down
46 changes: 39 additions & 7 deletions src/BizHawk.Emulation.Common/Base Implementations/MemoryDomain.cs
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Expand Up @@ -22,8 +22,6 @@ public enum Endian

private const string ERR_MSG_BUFFER_WRONG_SIZE = "Invalid length of values array";

private const string ERR_MSG_UNALIGNED = "The API contract doesn't define what to do for unaligned reads and writes!";

public string Name { get; protected set; }

public long Size { get; protected set; }
Expand Down Expand Up @@ -93,7 +91,7 @@ public virtual void BulkPeekByte(Range<long> addresses, byte[] values)
{
if (addresses is null) throw new ArgumentNullException(paramName: nameof(addresses));
if (values is null) throw new ArgumentNullException(paramName: nameof(values));
if ((long) addresses.Count() != values.Length) throw new InvalidOperationException(ERR_MSG_BUFFER_WRONG_SIZE);
if ((long) addresses.Count() > values.Length) throw new InvalidOperationException(ERR_MSG_BUFFER_WRONG_SIZE);

using (this.EnterExit())
{
Expand All @@ -104,15 +102,26 @@ public virtual void BulkPeekByte(Range<long> addresses, byte[] values)
}
}

public virtual void BulkPokeByte(long startAddress, Span<byte> values)
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{
using (this.EnterExit())
{
long address = startAddress;
for (var i = 0; i < values.Length; i++, address++)
{
PokeByte(address, values[i]);
}
}
}

public virtual void BulkPeekUshort(Range<long> addresses, bool bigEndian, ushort[] values)
{
if (addresses is null) throw new ArgumentNullException(paramName: nameof(addresses));
if (values is null) throw new ArgumentNullException(paramName: nameof(values));

var start = addresses.Start;
var end = addresses.EndInclusive + 1;
if ((start & 0b1) is not 0 || (end & 0b1) is not 0) throw new InvalidOperationException(ERR_MSG_UNALIGNED);
if (values.LongLength * sizeof(ushort) != end - start) throw new InvalidOperationException(ERR_MSG_BUFFER_WRONG_SIZE); // a longer array could be valid, but nothing needs that so don't support it for now
if (values.LongLength * sizeof(ushort) < end - start) throw new InvalidOperationException(ERR_MSG_BUFFER_WRONG_SIZE);

using (this.EnterExit())
{
Expand All @@ -123,15 +132,26 @@ public virtual void BulkPeekUshort(Range<long> addresses, bool bigEndian, ushort
}
}

public virtual void BulkPokeUshort(long startAddress, bool bigEndian, Span<ushort> values)
{
using (this.EnterExit())
{
long address = startAddress;
for (var i = 0; i < values.Length; i++, address += sizeof(ushort))
{
PokeUshort(address, values[i], bigEndian);
}
}
}

public virtual void BulkPeekUint(Range<long> addresses, bool bigEndian, uint[] values)
{
if (addresses is null) throw new ArgumentNullException(paramName: nameof(addresses));
if (values is null) throw new ArgumentNullException(paramName: nameof(values));

var start = addresses.Start;
var end = addresses.EndInclusive + 1;
if ((start & 0b11) is not 0 || (end & 0b11) is not 0) throw new InvalidOperationException(ERR_MSG_UNALIGNED);
if (values.LongLength * sizeof(uint) != end - start) throw new InvalidOperationException(ERR_MSG_BUFFER_WRONG_SIZE); // `!=` not `<`, per `BulkPeekUshort`
if (values.LongLength * sizeof(uint) < end - start) throw new InvalidOperationException(ERR_MSG_BUFFER_WRONG_SIZE);

using (this.EnterExit())
{
Expand All @@ -142,6 +162,18 @@ public virtual void BulkPeekUint(Range<long> addresses, bool bigEndian, uint[] v
}
}

public virtual void BulkPokeUint(long startAddress, bool bigEndian, Span<uint> values)
{
using (this.EnterExit())
{
long address = startAddress;
for (var i = 0; i < values.Length; i++, address += sizeof(uint))
{
PokeUint(address, values[i], bigEndian);
}
}
}

public virtual void SendCheatToCore(int addr, byte value, int compare, int compare_type) { }

/// <summary>
Expand Down
12 changes: 2 additions & 10 deletions src/BizHawk.Emulation.Cores/Computers/Doom/DSDA.IMemoryDomains.cs
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Expand Up @@ -232,12 +232,8 @@ public override void BulkPeekUshort(Range<long> addresses, bool bigEndian, ushor
var start = addresses.Start;
var end = addresses.EndInclusive + 1;

if ((start & 1) != 0 || (end & 1) != 0)
throw new InvalidOperationException("The API contract doesn't define what to do for unaligned reads and writes!");

if (values.LongLength * 2 != end - start)
if (values.LongLength * sizeof(ushort) < end - start)
{
// a longer array could be valid, but nothing needs that so don't support it for now
throw new InvalidOperationException("Invalid length of values array");
}

Expand All @@ -262,12 +258,8 @@ public override void BulkPeekUint(Range<long> addresses, bool bigEndian, uint[]
var start = addresses.Start;
var end = addresses.EndInclusive + 1;

if ((start & 3) != 0 || (end & 3) != 0)
throw new InvalidOperationException("The API contract doesn't define what to do for unaligned reads and writes!");

if (values.LongLength * 4 != end - start)
if (values.LongLength * sizeof(uint) < end - start)
{
// a longer array could be valid, but nothing needs that so don't support it for now
throw new InvalidOperationException("Invalid length of values array");
}

Expand Down
12 changes: 2 additions & 10 deletions src/BizHawk.Emulation.Cores/Consoles/Nintendo/3DS/Encore.IMemoryDomains.cs
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Expand Up @@ -222,12 +222,8 @@ public override void BulkPeekUshort(Range<long> addresses, bool bigEndian, ushor
var start = addresses.Start;
var end = addresses.EndInclusive + 1;

if ((start & 1) != 0 || (end & 1) != 0)
throw new InvalidOperationException("The API contract doesn't define what to do for unaligned reads and writes!");

if (values.LongLength * 2 != end - start)
if (values.LongLength * sizeof(ushort) < end - start)
{
// a longer array could be valid, but nothing needs that so don't support it for now
throw new InvalidOperationException("Invalid length of values array");
}

Expand All @@ -250,12 +246,8 @@ public override void BulkPeekUint(Range<long> addresses, bool bigEndian, uint[]
var start = addresses.Start;
var end = addresses.EndInclusive + 1;

if ((start & 3) != 0 || (end & 3) != 0)
throw new InvalidOperationException("The API contract doesn't define what to do for unaligned reads and writes!");

if (values.LongLength * 4 != end - start)
if (values.LongLength * sizeof(uint) < end - start)
{
// a longer array could be valid, but nothing needs that so don't support it for now
throw new InvalidOperationException("Invalid length of values array");
}

Expand Down
2 changes: 1 addition & 1 deletion src/BizHawk.Emulation.Cores/Waterbox/WaterboxMemoryDomain.cs
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Expand Up @@ -338,7 +338,7 @@ public override void BulkPeekByte(Range<long> addresses, byte[] values)
_read8.Access((IntPtr)p, addresses.Start, (long)addresses.Count());
}

public void BulkPokeByte(long addr, Span<byte> values)
public override void BulkPokeByte(long addr, Span<byte> values)
{
if ((ulong)addr + (ulong)values.Length > (ulong)Size || addr < 0) throw new ArgumentOutOfRangeException(nameof(addr), message: AddressRangeError);

Expand Down
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