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Re: [Lightning] Reducing opcode permutations


From: Paolo Bonzini
Subject: Re: [Lightning] Reducing opcode permutations
Date: Fri, 28 Mar 2008 17:20:27 +0100
User-agent: Thunderbird 2.0.0.12 (Macintosh/20080213)


jit_movi_i(JIT_R1, INT_MAX)     // R1 = 2^31
jit_addci_i(JIT_R0, JIT_R1, 1)   // R0 = R1 + 1, set carry
jit_addxi_i(JIT_R2, JIT_R0, 0)   // R2 = R0 + 0 + carry

Don't confuse carry with overflow. Carry is the same for integer and unsigned integer. Overflow differs, but what tests overflow is boadd/bosub, not addc/addx.

Paolo




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