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Re: [Lightning] How to use jit_ldxr_l
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From: |
Paolo Bonzini |
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Subject: |
Re: [Lightning] How to use jit_ldxr_l |
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Date: |
Wed, 21 Jul 2010 18:07:57 +0200 |
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User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.10) Gecko/20100621 Fedora/3.0.5-1.fc13 Lightning/1.0b2pre Thunderbird/3.0.5 |
On 07/21/2010 04:47 PM, Mathieu Suen wrote:
Hi,
I have some question concerning the ldxr/ldxi/ldr/ldi instruction.
Am I right to say that in Intel it is similar to the lea instruction?
No, ld/st are a move from/to memory.
If yes I am wondering what is the meaning of
jit_ldxr_p(JIT_R0, JIT_R1, ...);
compare to
jit_ldxr_i(JIT_R0, JIT_R1, 3);
This is wrong. The second source operand must be a register, as in all
jit_XXXr_YY instruction.
I mgiht not using the jit_ldxr_i / jit_ldxr_p correctly.
jit_ldxr_p and jit_ldxr_l (jit_ldxr_i) are exactly the same, but
jit_ldxr_i sign-extends the 32-bit value to 64 bits on 64-bit
architectures. jit_ldxr_ui zero-extends.
Paolo