These are mapped onto some of the normal load instructions, when the destination is the zero register. Other load insns do fault even when targeting the zero register.
Signed-off-by: Richard Henderson <r...@twiddle.net> --- target-tilegx/translate.c | 40 ++++++++++++++++++++++++++-------------- 1 file changed, 26 insertions(+), 14 deletions(-) diff --git a/target-tilegx/translate.c b/target-tilegx/translate.c index 8fee60c..6ab66f9 100644 --- a/target-tilegx/translate.c +++ b/target-tilegx/translate.c @@ -496,6 +496,7 @@ static TileExcp gen_rr_opcode(DisasContext *dc, unsigned opext, const char *mnemonic; TCGMemOp memop; TileExcp ret = TILEGX_EXCP_NONE; + bool prefetch_nofault = false; /* Eliminate instructions with no output before doing anything else. */ switch (opext) { @@ -609,27 +610,30 @@ static TileExcp gen_rr_opcode(DisasContext *dc, unsigned opext, return TILEGX_EXCP_OPCODE_UNIMPLEMENTED; case OE_RR_X1(LD1S): memop = MO_SB; - mnemonic = "ld1s"; + mnemonic = "ld1s"; /* prefetch_l1_fault */ goto do_load; case OE_RR_X1(LD1U): memop = MO_UB; - mnemonic = "ld1u"; + mnemonic = "ld1u"; /* prefetch, prefetch_l1 */ + prefetch_nofault = (dest == TILEGX_R_ZERO); goto do_load; case OE_RR_X1(LD2S): memop = MO_TESW; - mnemonic = "ld2s"; + mnemonic = "ld2s"; /* prefetch_l2_fault */ goto do_load; case OE_RR_X1(LD2U): memop = MO_TEUW; - mnemonic = "ld2u"; + mnemonic = "ld2u"; /* prefetch_l2 */ + prefetch_nofault = (dest == TILEGX_R_ZERO); goto do_load; case OE_RR_X1(LD4S): memop = MO_TESL; - mnemonic = "ld4s"; + mnemonic = "ld4s"; /* prefetch_l3_fault */ goto do_load; case OE_RR_X1(LD4U): memop = MO_TEUL; - mnemonic = "ld4u"; + mnemonic = "ld4u"; /* prefetch_l3 */ + prefetch_nofault = (dest == TILEGX_R_ZERO); goto do_load; case OE_RR_X1(LDNT1S): memop = MO_SB; @@ -663,7 +667,9 @@ static TileExcp gen_rr_opcode(DisasContext *dc, unsigned opext, memop = MO_TEQ; mnemonic = "ld"; do_load: - tcg_gen_qemu_ld_tl(tdest, tsrca, dc->mmuidx, memop); + if (!prefetch_nofault) { + tcg_gen_qemu_ld_tl(tdest, tsrca, dc->mmuidx, memop); + } break; case OE_RR_X1(LDNA): tcg_gen_andi_tl(tdest, tsrca, ~7); @@ -1442,6 +1448,7 @@ static TileExcp gen_rri_opcode(DisasContext *dc, unsigned opext, { TCGv tdest = dest_gr(dc, dest); TCGv tsrca = load_gr(dc, srca); + bool prefetch_nofault = false; const char *mnemonic; TCGMemOp memop; int i2, i3; @@ -1491,27 +1498,30 @@ static TileExcp gen_rri_opcode(DisasContext *dc, unsigned opext, break; case OE_IM(LD1S_ADD, X1): memop = MO_SB; - mnemonic = "ld1s_add"; + mnemonic = "ld1s_add"; /* prefetch_add_l1_fault */ goto do_load_add; case OE_IM(LD1U_ADD, X1): memop = MO_UB; - mnemonic = "ld1u_add"; + mnemonic = "ld1u_add"; /* prefetch_add_l1 */ + prefetch_nofault = (dest == TILEGX_R_ZERO); goto do_load_add; case OE_IM(LD2S_ADD, X1): memop = MO_TESW; - mnemonic = "ld2s_add"; + mnemonic = "ld2s_add"; /* prefetch_add_l2_fault */ goto do_load_add; case OE_IM(LD2U_ADD, X1): memop = MO_TEUW; - mnemonic = "ld2u_add"; + mnemonic = "ld2u_add"; /* prefetch_add_l2 */ + prefetch_nofault = (dest == TILEGX_R_ZERO); goto do_load_add; case OE_IM(LD4S_ADD, X1): memop = MO_TESL; - mnemonic = "ld4s_add"; + mnemonic = "ld4s_add"; /* prefetch_add_l3_fault */ goto do_load_add; case OE_IM(LD4U_ADD, X1): memop = MO_TEUL; - mnemonic = "ld4u_add"; + mnemonic = "ld4u_add"; /* prefetch_add_l3 */ + prefetch_nofault = (dest == TILEGX_R_ZERO); goto do_load_add; case OE_IM(LDNT1S_ADD, X1): memop = MO_SB; @@ -1545,7 +1555,9 @@ static TileExcp gen_rri_opcode(DisasContext *dc, unsigned opext, memop = MO_TEQ; mnemonic = "ld_add"; do_load_add: - tcg_gen_qemu_ld_tl(tdest, tsrca, dc->mmuidx, memop); + if (!prefetch_nofault) { + tcg_gen_qemu_ld_tl(tdest, tsrca, dc->mmuidx, memop); + } tcg_gen_addi_tl(dest_gr(dc, srca), tsrca, imm); break; case OE_IM(LDNA_ADD, X1): -- 2.4.3