Michael Schnell schrieb:
On 08/29/2011 05:58 PM, Hans-Peter Diettrich wrote:
That is why I am astonished that converting Java-Bytecode to Dalvik
code should be an easy task.
A stackbased internal or intermediate representation is the most
general one, from which a compiler can decide which registers to use
for expression evaluation etc. FPC itself uses registers only for the
actual code generation, depending on how many registers are available
on the target machine.
I don't see what you mean here. While of course FPC does acknowledge the
count and kind of registers with targets like ARM or X86 or X86-64, Sven
reported that his port for Java targets creates register-ignorant (stack
based) code for standard (SUN) virtual Java machines and the
"dex-converter" by Google converts this to 16-bit-wide Dalvik code which
introduces Register notation.
The FPC internal representation (code tree nodes) has no notion of
registers. This is (also) due to the fact, that a register allocator can
work reasonably only after the entire code of a subroutine is known.
When the target is a registerless VM, the register allocator never is
invoked.
DoDi
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