UML Instruction Reference

Introduction

UML is the instruction set used by MAME’s recompiler framework. Front-ends translate code running on the guest CPUs to UML instructions, and back-ends convert the UML instructions to a form that can be executed or interpreted on the host system.

Flow control

COMMENT

Insert a comment into logged UML code.

Disassembly	Usage
comment string	UML_COMMENT(block, string);

Operands

string

The comment text as a pointer to a NUL-terminated string. This must remain valid until code is generated for the block.

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

NOP

No operation.

Disassembly	Usage
nop	UML_NOP(block);

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

LABEL

Associate a location with a label number local to the current generated code block. Label numbers must not be reused within a generated code block. The JMP instruction may be used to transfer control to the location associated with a label number.

Disassembly	Usage
label label	UML_LABEL(block, label);

Operands

label (label number)

The label number to associate with the current location. A label number must not be used more than once within a generated code block.

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

HANDLE

Mark a location as an entry point of a subroutine. Subroutines may be called using the CALLH and EXH instructions, and also by the HASHJMP <umlinst-hashjmp> if no location is associated with the specified mode and emulated program counter.

Disassembly	Usage
handle handle	UML_HANDLE(block, handle);

Operands

handle (code handle)

The code handle to bind to the current location. The handle must already be allocated, and must not have been bound since the last generated code reset (all handles are implicitly unbound when resetting the generated code cache).

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

HASH

Associate a location with the specified mode and emulated program counter values. The HASHJMP instruction may be used to transfer control to the location associated with a mode and emulated program counter value.

This is usually used to mark the location of the generated code for an emulated instruction or sequence of instructions.

Disassembly	Usage
hash mode,pc	UML_HASH(block, mode, pc);

Operands

mode (32-bit – immediate, map variable)

The mode to associate with the current location in the generated code. Must be greater than or equal to zero and less than the number of modes specified when creating the recompiler context.

pc (32-bit – immediate, map variable)

The emulated program counter value to associate with the current location in the generated code.

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

JMP

Jump to the location associated with a label number within the current block.

Disassembly	Usage
jmp label jmp label,cond	UML_JMP(block, label); UML_JMPc(block, cond, label);

Operands

label (label number)

The label number associated with the location to jump to in the current generated code block. The label number must be associated with a location in the generated code block before the block is finalised.

cond (condition)

If supplied, a condition that must be met to jump to the specified label. If the condition is not met, execution will continue with the following instruction.

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

CALLH

Call the subroutine beginning at the specified code handle.

Disassembly	Usage
callh handle callh handle,cond	UML_CALLH(block, handle); UML_CALLHc(block, handle, cond);

Operands

handle (code handle)

Handle located at the entry point of the subroutine to call. The handle must already be allocated but does not need to be bound until the instruction is executed. Calling a handle that was unbound at code generation time may produce less efficient code than calling a handle that was already bound.

cond (condition)

If supplied, a condition that must be met for the subroutine to be called. If the condition is not met, the subroutine will not be called.

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

EXH

Set the EXP register and call the subroutine beginning at the specified code handle. The EXP register is a 32-bit special function register that may be retrieved with the GETEXP instruction.

Disassembly	Usage
exh handle,arg exh handle,arg,cond	UML_EXH(block, handle, arg); UML_EXHc(block, handle, arg, cond);

Operands

handle (code handle)

Handle located at the entry point of the subroutine to call. The handle must already be allocated but does not need to be bound until the instruction is executed. Calling a handle that was unbound at code generation time may produce less efficient code than calling a handle that was already bound.

arg (32-bit – memory, integer register, immediate, map variable)

Value to store in the EXP register.

cond (condition)

If supplied, a condition that must be met for the subroutine to be called. If the condition is not met, the subroutine will not be called and the EXP register will not be modified.

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

Simplification rules

• Immediate values for the arg operand are truncated to 32 bits.

RET

Return from a subroutine, transferring control to the instruction following the CALLH or EXH instruction used to call the subroutine. This instruction must only be used within generated code subroutines. The EXIT instruction must be used to exit from the generated code.

Disassembly	Usage
ret ret cond	UML_RET(block); UML_RETc(block, cond);

Operands

cond (condition)

If supplied, a condition that must be met to return from the subroutine. If the condition is not met, execution will continue with the following instruction.

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

HASHJMP

Unwind all nested generated code subroutine frames and transfer control to the location associated with the specified mode and emulated program counter values. If no location is associated with the specified mode and program counter values, call the subroutine beginning at the specified code handle. Note that all nested generated code subroutine frames are unwound in either case.

This is usually used to jump to the generated code corresponding to the emulated code at a particular address when it is not known to be in the current generated code block or when the mode changes.

Disassembly	Usage
hashjmp mode,pc,handle	UML_HASHJMP(block, mode, pc, handle);

Operands

mode (32-bit – memory, integer register, immediate, map variable)

The mode associated with the location in the generated code to transfer control to. Must be greater than or equal to zero and less than the number of modes specified when creating the recompiler context.

pc (32-bit – memory, integer register, immediate, map variable)

The emulated program counter value associated with the location in the generated code to transfer control to.

handle (code handle)

Handle located at the entry point of the subroutine to call if no location in the generated code is associated with the specified mode and emulated program counter values. The handle must already be allocated but does not need to be bound until the instruction is executed. Calling a handle that was unbound at code generation time may produce less efficient code than calling a handle that was already bound.

Flags

carry (C)	Undefined.
overflow (V)	Undefined.
zero (Z)	Undefined.
sign (S)	Undefined.
unordered (U)	Undefined.

EXIT

Exit from the generated code, returning control to the caller. May be used from within any level of nested subroutine calls in the generated code.

Disassembly	Usage
exit arg, exit arg,,cond	UML_EXIT(block, arg); UML_EXITc(block, arg, cond);

Operands

arg (32-bit – memory, integer register, immediate, map variable)

The value to return to the caller.

cond (condition)

If supplied, a condition that must be met to exit from the generated code. If the condition is not met, execution will continue with the following instruction.

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

Simplification rules

• Immediate values for the arg operand are truncated to 32 bits.

CALLC

Call a C function with the signature void (*)(void *).

Disassembly	Usage
callc func,arg callc func,arg,cond	UML_CALLC(block, func, arg); UML_CALLCc(block, func, arg, cond);

Operands

func (C function)

Function pointer to the function to call.

arg (memory)

Argument to pass to the function.

cond (condition)

If supplied, a condition that must be met for the function to be called. If the condition is not met, the function will not be called.

Flags

carry (C)	Undefined.
overflow (V)	Undefined.
zero (Z)	Undefined.
sign (S)	Undefined.
unordered (U)	Undefined.

DEBUG

Call the debugger instruction hook function if appropriate.

If the debugger is active, this should be executed before each emulated instruction. Any emulated CPU state kept in UML registers should be flushed to memory before executing this instruction and reloaded afterwards to ensure the debugger can display and modify values correctly.

Disassembly	Usage
debug pc	UML_DEBUG(block, pc);

Operands

pc (32-bit – memory, integer register, immediate, map variable)

The emulated program counter value to supply to the debugger instruction hook function.

Flags

carry (C)	Undefined.
overflow (V)	Undefined.
zero (Z)	Undefined.
sign (S)	Undefined.
unordered (U)	Undefined.

Simplification rules

• Immediate values for the pc operand are truncated to 32 bits.

BREAK

Break into the host debugger if attached. Has no effect or crashes if no host debugger is attached depending on the host system and configuration. This is intended as a developer aid and should not be left in final code.

Disassembly	Usage
break	UML_BREAK(block);

Flags

carry (C)	Undefined.
overflow (V)	Undefined.
zero (Z)	Undefined.
sign (S)	Undefined.
unordered (U)	Undefined.

Data movement

MOV

Copy an integer value.

Disassembly	Usage
mov dst,src mov dst,src,cond dmov dst,src dmov dst,src,cond	UML_MOV(block, dst, src); UML_MOVc(block, cond, dst, src); UML_DMOV(block, dst, src); UML_DMOVc(block, cond, dst, src);

Operands

dst (32-bit or 64-bit – memory, integer register)

The destination where the value will be copied to.

src (32-bit or 64-bit – memory, integer register, immediate, map variable)

The source value to copy.

cond (condition)

If supplied, a condition that must be met to copy the value. If the condition is not met, the instruction will have no effect.

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

Simplification rules

• Immediate values for the src operand are truncated to the instruction size.

• Converted to NOP if the src and dst operands refer to the same memory location or register and the instruction size is no larger than the destination size.

FMOV

Copy a floating point value. The binary value will be preserved even if it is not a valid representation of a floating point number.

Disassembly	Usage
fsmov dst,src fsmov dst,src,cond fdmov dst,src fdmov dst,src,cond	UML_FSMOV(block, dst, src); UML_FSMOVc(block, cond, dst, src); UML_FDMOV(block, dst, src); UML_FDMOVc(block, cond, dst, src);

Operands

dst (32-bit or 64-bit – memory, floating point register)

The destination where the value will be copied to.

src (32-bit or 64-bit – memory, floating point register)

The source value to copy.

cond (condition)

If supplied, a condition that must be met to copy the value. If the condition is not met, the instruction will have no effect.

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

Simplification rules

• Converted to NOP if the src and dst operands refer to the same memory location or register.

FCOPYI

Reinterpret an integer value as a floating point value. The binary value will be preserved even if it is not a valid representation of a floating point number.

Disassembly	Usage
fscopyi dst,src fdcopyi dst,src	UML_FSCOPYI(block, dst, src); UML_FDCOPYI(block, dst, src);

Operands

dst (32-bit or 64-bit – memory, floating point register)

The destination where the value will be copied to.

src (32-bit or 64-bit – memory, integer register)

The source value to copy.

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

ICOPYF

Reinterpret a floating point value as an integer value. The binary value will be preserved even if it is not a valid representation of a floating point number.

Disassembly	Usage
icopyfs dst,src icopyfd dst,src	UML_ICOPYFS(block, dst, src); UML_ICOPYFD(block, dst, src);

Operands

dst (32-bit or 64-bit – memory, integer register)

The destination where the value will be copied to.

src (32-bit or 64-bit – memory, floating point register)

The source value to copy.

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

LOAD

Load an unsigned integer value from a memory location with variable displacement. The value is zero-extended to the size of the destination. Host system rules for integer alignment must be followed.

Disassembly	Usage
load dst,base,index,size_scale dload dst,base,index,size_scale	UML_LOAD(block, dst, base, index, size, scale); UML_DLOAD(block, dst, base, index, size, scale);

Operands

dst (32-bit or 64-bit – memory, integer register)

The destination where the value read from memory will be stored.

base (memory)

The base address of the area of memory to read from.

index (32-bit – memory, integer register, immediate, map variable)

The displacement value added to the base address to calculate the address to read from. This value may be scaled by a factor of 1, 2, 4 or 8 depending on the scale operand. Note that this is always a 32-bit operand interpreted as a signed integer, irrespective of the instruction size.

size (access size)

The size of the value to read. Must be SIZE_BYTE (8-bit), SIZE_WORD (16-bit), SIZE_DWORD (32-bit) or SIZE_QWORD (64-bit). Note that this operand controls the size of the value read from memory while the instruction size sets the size of the dst operand.

scale (index scale)

The scale factor to apply to the index operand. Must be SCALE_x1, SCALE_x2, SCALE_x4 or SCALE_x8 to multiply by 1, 2, 4 or 8, respectively (shift left by 0, 1, 2 or 3 bits).

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

LOADS

Load a signed integer value from a memory location with variable displacement. The value is sign-extended to the size of the destination. Host system rules for integer alignment must be followed.

Disassembly	Usage
loads dst,base,index,size_scale dloads dst,base,index,size_scale	UML_LOADS(block, dst, base, index, size, scale); UML_DLOADS(block, dst, base, index, size, scale);

Operands

dst (32-bit or 64-bit – memory, integer register)

The destination where the value read from memory will be stored.

base (memory)

The base address of the area of memory to read from.

index (32-bit – memory, integer register, immediate, map variable)

The displacement value added to the base address to calculate the address to read from. This value may be scaled by a factor of 1, 2, 4 or 8 depending on the scale operand. Note that this is always a 32-bit operand interpreted as a signed integer, irrespective of the instruction size.

size (access size)

The size of the value to read. Must be SIZE_BYTE (8-bit), SIZE_WORD (16-bit), SIZE_DWORD (32-bit) or SIZE_QWORD (64-bit). Note that this operand controls the size of the value read from memory while the instruction size sets the size of the dst operand.

scale (index scale)

The scale factor to apply to the index operand. Must be SCALE_x1, SCALE_x2, SCALE_x4 or SCALE_x8 to multiply by 1, 2, 4 or 8, respectively (shift left by 0, 1, 2 or 3 bits).

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

STORE

Store an integer value to a location in memory with variable displacement. Host system rules for integer alignment must be followed.

Disassembly	Usage
store base,index,src,size_scale dstore base,index,src,size_scale	UML_STORE(block, base, index, src, size, scale); UML_DSTORE(block, base, index, src, size, scale);

Operands

base (memory)

The base address of the area of memory to write to.

index (32-bit – memory, integer register, immediate, map variable)

The displacement value added to the base address to calculate the address to write to. This value may be scaled by a factor of 1, 2, 4 or 8 depending on the scale operand. Note that this is always a 32-bit operand interpreted as a signed integer, irrespective of the instruction size.

src (32-bit or 64-bit – memory, integer register, immediate, map variable)

The value to write to memory.

size (access size)

The size of the value to write. Must be SIZE_BYTE (8-bit), SIZE_WORD (16-bit), SIZE_DWORD (32-bit) or SIZE_QWORD (64-bit). Note that this operand controls the size of the value written to memory while the instruction size sets the size of the src operand.

scale (index scale)

The scale factor to apply to the index operand. Must be SCALE_x1, SCALE_x2, SCALE_x4 or SCALE_x8 to multiply by 1, 2, 4 or 8, respectively (shift left by 0, 1, 2 or 3 bits).

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

FLOAD

Load a floating point value from a memory location with variable displacement. The binary value will be preserved even if it is not a valid representation of a floating point number. Host system rules for memory access alignment must be followed.

Disassembly	Usage
fsload dst,base,index fdload dst,base,index	UML_FSLOAD(block, dst, base, index); UML_FDLOAD(block, dst, base, index);

Operands

dst (32-bit or 64-bit – memory, floating point register)

The destination where the value read from memory will be stored.

base (memory)

The base address of the area of memory to read from.

index (32-bit – memory, integer register, immediate, map variable)

The displacement value added to the base address to calculate the address to read from. This value will be scaled by the instruction size (multiplied by 4 or 8). Note that this is always a 32-bit operand interpreted as a signed integer, irrespective of the instruction size.

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

FSTORE

Store a floating point value to a memory location with variable displacement. The binary value will be preserved even if it is not a valid representation of a floating point number. Host system rules for memory access alignment must be followed.

Disassembly	Usage
fsstore base,index,src fdstore base,index,src	UML_FSSTORE(block, base, index, src); UML_FDSTORE(block, base, index, src);

Operands

base (memory)

The base address of the area of memory to write to.

index (32-bit – memory, integer register, immediate, map variable)

The displacement value added to the base address to calculate the address to write to. This value will be scaled by the instruction size (multiplied by 4 or 8). Note that this is always a 32-bit operand interpreted as a signed integer, irrespective of the instruction size.

src (32-bit or 64-bit – memory, floating point register)

The value to write to memory.

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

GETEXP

Copy the value of the EXP register. The EXP register can be set using the EXH instruction.

Disassembly	Usage
getexp dst	UML_GETEXP(block, dst);

Operands

dst (32-bit – memory, integer register)

The destination to copy the value of the EXP register to. Note that the EXP register can only hold a 32-bit value.

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

MAPVAR

Set the value of a map variable starting at the current location in the current generated code block.

Disassembly	Usage
mapvar mapvar,value	UML_MAPVAR(block, mapvar, value);

Operands

mapvar (map variable)

The map variable to set the value of.

value (32-bit – immediate, map variable)

The value to set the map variable to. Note that map variables can only hold 32-bit values.

Flags

carry (C)	Unchanged.
overflow (V)	Unchanged.
zero (Z)	Unchanged.
sign (S)	Unchanged.
unordered (U)	Unchanged.

RECOVER

Retrieve the value of a map variable at the location of the call instruction in the outermost generated code frame. This instruction should only be used from within a generated code subroutine. Results are undefined if this instruction is executed from outside any generated code subroutines.

Disassembly	Usage
recover dst,mapvar	UML_RECOVER(block, dst, mapvar);

Operands

dst (32-bit – memory, integer register)

The destination to copy the value of the map variable to. Note that map variables can only hold 32-bit values.

mapvar (map variable)

The map variable to retrieve the value of from the outermost generated code frame.

Flags

carry (C)	Undefined.
overflow (V)	Undefined.
zero (Z)	Undefined.
sign (S)	Undefined.
unordered (U)	Undefined.

Emulated memory access

READ

Read from an emulated address space. The access mask is implied to have all bits set.

Disassembly	Usage
read dst,addr,space_size dread dst,addr,space_size	UML_READ(block, dst, addr, size, space); UML_DREAD(block, dst, addr, size, space);

Operands

dst (32-bit or 64-bit – memory, integer register)

The destination where the value read from the emulated address space will be stored.

addr (32-bit – memory, integer register, immediate, map variable)

The address to read from in the emulated address space. Note that this is always a 32-bit operand, irrespective of the instruction size.

size (access size)

The size of the emulated memory access. Must be SIZE_BYTE (8-bit), SIZE_WORD (16-bit), SIZE_DWORD (32-bit) or SIZE_QWORD (64-bit). Note that this operand controls the size of the emulated memory access while the instruction size sets the size of the dst operand.

space (address space number)

An integer identifying the address space to read from. May be SPACE_PROGRAM, SPACE_DATA, SPACE_IO or SPACE_OPCODES for one of the common CPU address spaces, or a non-negative integer cast to memory_space.

Flags

carry (C)	Undefined.
overflow (V)	Undefined.
zero (Z)	Undefined.
sign (S)	Undefined.
unordered (U)	Undefined.

Simplification rules

• Immediate values for the addr operand are truncated to 32 bits.

READM

Read from an emulated address space with access mask specified.

Disassembly	Usage
readm dst,addr,mask,space_size dreadm dst,addr,mask,space_size	UML_READM(block, dst, addr, mask, size, space); UML_DREADM(block, dst, addr, mask, size, space);

Operands

dst (32-bit or 64-bit – memory, integer register)

The destination where the value read from the emulated address space will be stored.

addr (32-bit – memory, integer register, immediate, map variable)

The address to read from in the emulated address space. Note that this is always a 32-bit operand, irrespective of the instruction size.

mask (32-bit or 64-bit – memory, integer register, immediate, map variable)

The access mask for the emulated memory access.

size (access size)

The size of the emulated memory access. Must be SIZE_BYTE (8-bit), SIZE_WORD (16-bit), SIZE_DWORD (32-bit) or SIZE_QWORD (64-bit). Note that this operand controls the size of the emulated memory access while the instruction size sets the size of the dst and mask operands.

space (address space number)

An integer identifying the address space to read from. May be SPACE_PROGRAM, SPACE_DATA, SPACE_IO or SPACE_OPCODES for one of the common CPU address spaces, or a non-negative integer cast to memory_space.

Flags

carry (C)	Undefined.
overflow (V)	Undefined.
zero (Z)	Undefined.
sign (S)	Undefined.
unordered (U)	Undefined.

Simplification rules

• Immediate values for the addr operand are truncated to 32 bits.

• Immediate values for the mask operand are truncated to the access size.

• Converted to READ if the mask operand is an immediate value with all bits set.

WRITE

Write to an emulated address space. The access mask is implied to have all bits set.

Disassembly	Usage
write addr,src,space_size dwrite addr,src,space_size	UML_WRITE(block, addr, src, size, space); UML_DWRITE(block, addr, src, size, space);

Operands

addr (32-bit – memory, integer register, immediate, map variable)

The address to write to in the emulated address space. Note that this is always a 32-bit operand, irrespective of the instruction size.

src (32-bit or 64-bit – memory, integer register, immediate, map variable)

The value to write to the emulated address space.

size (access size)

The size of the emulated memory access. Must be SIZE_BYTE (8-bit), SIZE_WORD (16-bit), SIZE_DWORD (32-bit) or SIZE_QWORD (64-bit). Note that this operand controls the size of the emulated memory access while the instruction size sets the size of the src operand.

space (address space number)

An integer identifying the address space to read from. May be SPACE_PROGRAM, SPACE_DATA, SPACE_IO or SPACE_OPCODES for one of the common CPU address spaces, or a non-negative integer cast to memory_space.

Flags

carry (C)	Undefined.
overflow (V)	Undefined.
zero (Z)	Undefined.
sign (S)	Undefined.
unordered (U)	Undefined.

Simplification rules

• Immediate values for the addr operand are truncated to 32 bits.

• Immediate values for the src operand are truncated to the access size.

WRITEM

Write to an emulated address space with access mask specified.

Disassembly	Usage
writem addr,src,mask,space_size dwritem addr,src,mask,space_size	UML_WRITEM(block, addr, src, mask, size, space); UML_DWRITEM(block, addr, src, mask, size, space);

Operands

addr (32-bit – memory, integer register, immediate, map variable)

The address to write to in the emulated address space. Note that this is always a 32-bit operand, irrespective of the instruction size.

src (32-bit or 64-bit – memory, integer register, immediate, map variable)

The value to write to the emulated address space.

mask (32-bit or 64-bit – memory, integer register, immediate, map variable)

The access mask for the emulated memory access.

size (access size)

The size of the emulated memory access. Must be SIZE_BYTE (8-bit), SIZE_WORD (16-bit), SIZE_DWORD (32-bit) or SIZE_QWORD (64-bit). Note that this operand controls the size of the emulated memory access while the instruction size sets the size of the src and mask operands.

space (address space number)

An integer identifying the address space to read from. May be SPACE_PROGRAM, SPACE_DATA, SPACE_IO or SPACE_OPCODES for one of the common CPU address spaces, or a non-negative integer cast to memory_space.

Flags

carry (C)	Undefined.
overflow (V)	Undefined.
zero (Z)	Undefined.
sign (S)	Undefined.
unordered (U)	Undefined.

Simplification rules

• Immediate values for the addr operand are truncated to 32 bits.

• Immediate values for the src and mask operands are truncated to the access size.

• Converted to WRITE if the mask operand is an immediate value with all bits set.

FREAD

Read a floating point value from an emulated address space. The binary value will be preserved even if it is not a valid representation of a floating point number. The access mask is implied to have all bits set.

Disassembly	Usage
fsread dst,addr,space_size fdread dst,addr,space_size	UML_FSREAD(block, dst, addr, space); UML_FDREAD(block, dst, addr, space);

Operands

dst (32-bit or 64-bit – memory, floating point register)

The destination where the value read from the emulated address space will be stored.

addr (32-bit – memory, integer register, immediate, map variable)

The address to read from in the emulated address space. Note that this is always a 32-bit operand, irrespective of the instruction size.

space (address space number)

An integer identifying the address space to read from. May be SPACE_PROGRAM, SPACE_DATA, SPACE_IO or SPACE_OPCODES for one of the common CPU address spaces, or a non-negative integer cast to memory_space.

Flags

carry (C)	Undefined.
overflow (V)	Undefined.
zero (Z)	Undefined.
sign (S)	Undefined.
unordered (U)	Undefined.

Simplification rules

• Immediate values for the addr operand are truncated to 32 bits.

FWRITE

Write a floating point value to an emulated address space. The binary value will be preserved even if it is not a valid representation of a floating point number. The access mask is implied to have all bits set.

Disassembly	Usage
fswrite addr,src,space_size fdwrite addr,src,space_size	UML_FSWRITE(block, addr, src, space); UML_FDWRITE(block, addr, src, space);

Operands

addr (32-bit – memory, integer register, immediate, map variable)

The address to write to in the emulated address space. Note that this is always a 32-bit operand, irrespective of the instruction size.

src (32-bit or 64-bit – memory, floating point register)

The value to write to the emulated address space. will be stored.

space (address space number)

An integer identifying the address space to read from. May be SPACE_PROGRAM, SPACE_DATA, SPACE_IO or SPACE_OPCODES for one of the common CPU address spaces, or a non-negative integer cast to memory_space.

Flags

carry (C)	Undefined.
overflow (V)	Undefined.
zero (Z)	Undefined.
sign (S)	Undefined.
unordered (U)	Undefined.

Simplification rules

• Immediate values for the addr operand are truncated to 32 bits.