Tinkering with Dreamcast's Sh4's architecture

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Re: Tinkering with Dreamcast's Sh4's architecture

Post by Ex-Cyber »

gcc doesn't know how to parse the asm to figure out whether the code is reading and/or writing any given variable:
Output operand expressions must be lvalues; the compiler can check this. The input operands need not be lvalues. The compiler cannot check whether the operands have data types that are reasonable for the instruction being executed. It does not parse the assembler instruction template and does not know what it means or even whether it is valid assembler input.
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Re: Tinkering with Dreamcast's Sh4's architecture

Post by N64VSNES »

Ex-Cyber wrote:gcc doesn't know how to parse the asm to figure out whether the code is reading and/or writing any given variable:
Output operand expressions must be lvalues; the compiler can check this. The input operands need not be lvalues. The compiler cannot check whether the operands have data types that are reasonable for the instruction being executed. It does not parse the assembler instruction template and does not know what it means or even whether it is valid assembler input.
Hmm, so if these constraints aren't passed the variables won't be updated?
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