| /* Copyright lowRISC contributors. */ |
| /* Licensed under the Apache License, Version 2.0, see LICENSE for details. */ |
| /* SPDX-License-Identifier: Apache-2.0 */ |
| |
| /* 256-bit multiply example. Loads two 256-bit words from DMem into w1, w0. |
| Multiplies usings BN.MULQACC with the result placed into w3, w2 (upper half |
| in w3). */ |
| |
| .section .text.start |
| /* Initialise WDRs before using them */ |
| bn.xor w2, w2, w2 |
| bn.xor w3, w3, w3 |
| |
| /* Load operands into WDRs */ |
| li x2, 0 |
| la x3, operand1 |
| bn.lid x2, 0(x3) |
| |
| li x2, 1 |
| la x3, operand2 |
| bn.lid x2, 0(x3) |
| |
| /* Perform the multiply, limbs are 64-bit. Each instance of `mulqacc` will |
| operate on two limbs as a 64-bit multiply produces a 128-bit result. */ |
| |
| /* limbs 0 & 1 */ |
| bn.mulqacc.Z w0.0, w1.0, 0 |
| |
| /* limbs 1 & 2 */ |
| bn.mulqacc w0.1, w1.0, 64 |
| bn.mulqacc.so w2.L, w0.0, w1.1, 64 |
| |
| /* limbs 2 & 3 */ |
| bn.mulqacc w0.2, w1.0, 0 |
| bn.mulqacc w0.1, w1.1, 0 |
| bn.mulqacc w0.0, w1.2, 0 |
| |
| /* limbs 3 & 4 */ |
| bn.mulqacc w0.3, w1.0, 64 |
| bn.mulqacc w0.2, w1.1, 64 |
| bn.mulqacc w0.1, w1.2, 64 |
| bn.mulqacc.so w2.U, w0.0, w1.3, 64 |
| |
| /* limbs 4 & 5 */ |
| bn.mulqacc w0.3, w1.1, 0 |
| bn.mulqacc w0.2, w1.2, 0 |
| bn.mulqacc w0.1, w1.3, 0 |
| |
| /* limbs 5 & 6 */ |
| bn.mulqacc w0.3, w1.2, 64 |
| bn.mulqacc.so w3.L, w0.2, w1.3, 64 |
| |
| /* limbs 6 & 7 */ |
| bn.mulqacc.so w3.U, w0.3, w1.3, 0 |
| |
| ecall |
| |
| .section .data |
| |
| /* 256-bit integer |
| |
| fbc20c8e4ba684f2 f6835831c3623f41 |
| 49de6d75d0221f41 61a5a8d66985591e |
| |
| (.quad below is in reverse order) */ |
| |
| operand1: |
| .quad 0x61a5a8d66985591e |
| .quad 0x49de6d75d0221f41 |
| .quad 0xf6835831c3623f41 |
| .quad 0xfbc20c8e4ba684f2 |
| |
| /* 256-bit integer |
| |
| 10ad673384d81d98 1a1c98e116948392 |
| 60f39da06db956ec 5de6ee4dbd0f089d |
| |
| (.quad below is in reverse order) */ |
| |
| operand2: |
| .quad 0x5de6ee4dbd0f089d |
| .quad 0x60f39da06db956ec |
| .quad 0x1a1c98e116948392 |
| .quad 0x10ad673384d81d98 |
| |
| /* Expected result is |
| w3 = |
| 1066a8691e3ddfee a0a622d04cfd63b4 |
| ea93fcc837b795eb 3f2b811bfa6dc7f2 |
| |
| w2 = |
| dad4a618536bfd33 565eff3285ab75a5 |
| 59b7199e0622d5ee ed40926c40529766 */ |
