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tcg: Introduce byte pointer arithmetic helpers

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Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Richard Henderson 2014-03-31 14:27:27 -07:00
parent 5c53bb8121
commit 52a1f64ec5
1 changed files with 45 additions and 0 deletions
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45
tcg/tcg.h
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@ -723,6 +723,51 @@ TCGv_i64 tcg_const_i64(int64_t val);
TCGv_i32 tcg_const_local_i32(int32_t val);
TCGv_i64 tcg_const_local_i64(int64_t val);
/**
* tcg_ptr_byte_diff
* @a, @b: addresses to be differenced
*
* There are many places within the TCG backends where we need a byte
* difference between two pointers. While this can be accomplished
* with local casting, it's easy to get wrong -- especially if one is
* concerned with the signedness of the result.
*
* This version relies on GCC's void pointer arithmetic to get the
* correct result.
*/
static inline ptrdiff_t tcg_ptr_byte_diff(void *a, void *b)
{
return a - b;
}
/**
* tcg_pcrel_diff
* @s: the tcg context
* @target: address of the target
*
* Produce a pc-relative difference, from the current code_ptr
* to the destination address.
*/
static inline ptrdiff_t tcg_pcrel_diff(TCGContext *s, void *target)
{
return tcg_ptr_byte_diff(target, s->code_ptr);
}
/**
* tcg_current_code_size
* @s: the tcg context
*
* Compute the current code size within the translation block.
* This is used to fill in qemu's data structures for goto_tb.
*/
static inline size_t tcg_current_code_size(TCGContext *s)
{
return tcg_ptr_byte_diff(s->code_ptr, s->code_buf);
}
/**
* tcg_qemu_tb_exec:
* @env: CPUArchState * for the CPU