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96893cc143
Fixes #844 This PR adds a new machine to the STD: `WriteOnceMemory`. This can be used in our RISC-V machine for bootloader inputs (#1203). Most of the issues mentioned in the issue were fixed in the meantime or had a simple workaround (like defining `let LATCH = 1`). The only remaining issues were in the machine detection, which I fixed here. I also re-factor two existing tests.
20 lines
830 B
NASM
20 lines
830 B
NASM
// Very simple write-once memory that let's you store any field element at
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// an address from 0 to N-1. Any value can be written only once, writing two
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// different values to the same address fails. If an uninitialized cell is
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// read, the returned values is unconstrained.
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// A typical use-case would be to pass the `value` column as an "external"
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// witness. This way the prover can provide some input vector and the program
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// can read the same input multiple times.
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machine WriteOnceMemory(LATCH, _) {
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// Accesses the memory cell at the given address. This can be used
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// both for reading and writing, e.g.:
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// instr mload X -> Y = memory.access X, Y ->;
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// instr mstore X, Y -> = memory.access X, Y ->;
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operation access ADDR, value ->;
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let LATCH = 1;
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let ADDR: col = |i| i;
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let value;
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} |