mirror of
https://github.com/logos-storage/plonky2.git
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36 lines
1.7 KiB
NASM
36 lines
1.7 KiB
NASM
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// Precompute a table of multiples of the BN254 point `Q = (Qx, Qy)`.
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// Let `(Qxi, Qyi) = i * Q`, then store in the `SEGMENT_KERNEL_BN_TABLE_Q` segment of memory the values
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// `i-1 => Qxi`, `i => Qyi if i < 16 else -Qy(32-i)` for `i in range(1, 32, 2)`.
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global bn_precompute_table:
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// stack: Qx, Qy, retdest
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PUSH precompute_table_contd DUP3 DUP3
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%jump(bn_double)
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precompute_table_contd:
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// stack: Qx2, Qy2, Qx, Qy, retdest
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PUSH 1
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bn_precompute_table_loop:
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// stack i, Qx2, Qy2, Qx, Qy, retdest
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PUSH 1 DUP2 SUB
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%stack (im, i, Qx2, Qy2, Qx, Qy, retdest) -> (i, Qy, im, Qx, i, Qx2, Qy2, Qx, Qy, retdest)
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%mstore_kernel(@SEGMENT_KERNEL_BN_TABLE_Q) %mstore_kernel(@SEGMENT_KERNEL_BN_TABLE_Q)
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// stack: i, Qx2, Qy2, Qx, Qy, retdest
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DUP1 PUSH 32 SUB PUSH 1 DUP2 SUB
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// stack: 31-i, 32-i, i, Qx2, Qy2, Qx, Qy, retdest
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DUP7 PUSH @BN_BASE SUB
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// TODO: Could maybe avoid storing Qx a second time here, not sure if it would be more efficient.
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%stack (Qyy, iii, ii, i, Qx2, Qy2, Qx, Qy, retdest) -> (iii, Qx, ii, Qyy, i, Qx2, Qy2, Qx, Qy, retdest)
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%mstore_kernel(@SEGMENT_KERNEL_BN_TABLE_Q) %mstore_kernel(@SEGMENT_KERNEL_BN_TABLE_Q)
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// stack: i, Qx2, Qy2, Qx, Qy, retdest
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PUSH 2 ADD
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// stack: i+2, Qx2, Qy2, Qx, Qy, retdest
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DUP1 PUSH 16 LT %jumpi(precompute_table_end)
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%stack (i, Qx2, Qy2, Qx, Qy, retdest) -> (Qx, Qy, Qx2, Qy2, precompute_table_loop_contd, i, Qx2, Qy2, retdest)
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%jump(bn_add_valid_points)
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precompute_table_loop_contd:
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%stack (Qx, Qy, i, Qx2, Qy2, retdest) -> (i, Qx2, Qy2, Qx, Qy, retdest)
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%jump(bn_precompute_table_loop)
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precompute_table_end:
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// stack: i, Qx2, Qy2, Qx, Qy, retdest
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%pop5 JUMP
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