Create an object at a given address: Difference between revisions

=={{header|M2000 Interpreter}}==

In M2000 we can create two kind of buffers, one for data, and one for code. Buffer for code is immutable at execution time. We can execute code by using an offset. Buffer for data is always mutable, but can't execute code.

There is no assembler x86 for M2000 yet, so we have to write code using a reference book and some subs for help

Memory addresses are nit the physical address, it's from virtual space.

<lang M2000 Interpreter>

Module CheckIt {

structure alfa {

val as long

}

Buffer Clear Beta as alfa*2

Print Beta(0) ' return address

Return Beta, 0!val:=500 ' unsigned integer 32 bit

Print Eval(Beta, 0!val)=500

Return Beta, 0!val:=0xFFFFFFFF

Print Eval(Beta, 0!val)=4294967295

Buffer Code ExecMem as byte*1024

Offset=0

EmbLong(0xb8, 5000) ' mov eax,5100

EmbByteLong(0x3,0x5, Beta(0)) ' add eax, [Beta(0)]

EmbLong(0xa3, Beta(1)) ' mov [Beta(1)], eax

EmbByte(0x31, 0xC0) ' xor eax, eax

Ret() ' Return

Execute Code ExecMem, 0

Print eval(Beta, 1!val)=4999

Sub Ret()

Return ExecMem, Offset:=0xC3

Offset++

End Sub

Sub EmbByte()

Return ExecMem, Offset:=Number, Offset+1:=Number

Offset+=2

End Sub

Sub EmbLong()

Return ExecMem, Offset:=Number, Offset+1:=Number as Long

Offset+=5

End Sub

Sub EmbByteLong()

Return ExecMem, Offset:=Number, Offset+1:=Number, Offset+2:=Number as Long

Offset+=6

End Sub

}

Checkit

</lang>