Björn Töpel <bjorn@xxxxxxxxxx> writes: > The range of valid address for RV64 (sv39 to sv57) are > 0xffffffff00000000 to 0xffffffffffffffff, so I think we can do better > than 6 insn, no? My gut feeling (I need to tinker a bit) is that 4 > should be sufficient. Ok, thinking a bit more about it; A proper address will at have at least 2B alignment, so that means that we can construct an address with lui, addi, and slli (31 bits). u64 addr = 0xffffffff12345678; u32 (imm |= 0xffffffffUL) >> 1; u32 upper = (imm + (1 << 11)) >> 12; u32 lower = imm & 0xfff; u32 rupper = upper | 0x80000; // for sign extend NB! Make sure it's !C insn, and emit: lui xx, rupper addi xx, xx, lower slli xx, xx, 1 Now we'll have fixed three insns. WDYT? Björn
