On 2/2/22 00:41, Richard Henderson wrote:
This is kinda sorta the opposite of the other tcg hosts, where
we get (normal) alignment checks for free with host SIGBUS and
need to add code to support unaligned accesses.
Fortunately, the ISA contains pairs of instructions that are
used to implement unaligned memory accesses. Use them.
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
tcg/mips/tcg-target.h | 2 -
tcg/mips/tcg-target.c.inc | 334 +++++++++++++++++++++++++++++++++++++-
2 files changed, 328 insertions(+), 8 deletions(-)
+static void __attribute__((unused))
+tcg_out_qemu_ld_unalign(TCGContext *s, TCGReg lo, TCGReg hi,
+ TCGReg base, MemOp opc, bool is_64)
Unaligned style to honor the function name? ;)
+static void __attribute__((unused))
+tcg_out_qemu_st_unalign(TCGContext *s, TCGReg lo, TCGReg hi,
+ TCGReg base, MemOp opc)
Ditto.
+ case MO_64 | MO_BSWAP:
+ if (TCG_TARGET_REG_BITS == 64) {
+ tcg_out_bswap64(s, TCG_TMP3, lo);
+ lo = TCG_TMP3;
+ } else if (use_mips32r2_instructions) {
+ tcg_out_opc_reg(s, OPC_WSBH, TCG_TMP0, 0, MIPS_BE ? hi : lo);
+ tcg_out_opc_reg(s, OPC_WSBH, TCG_TMP1, 0, MIPS_BE ? lo : hi);
+ tcg_out_opc_sa(s, OPC_ROTR, TCG_TMP0, TCG_TMP0, 16);
+ tcg_out_opc_sa(s, OPC_ROTR, TCG_TMP1, TCG_TMP1, 16);
+ hi = MIPS_BE ? TCG_TMP0 : TCG_TMP1;
+ lo = MIPS_BE ? TCG_TMP1 : TCG_TMP0;
+ } else {
+ tcg_out_bswap32(s, TCG_TMP3, MIPS_BE ? lo : hi, 0);
+ tcg_out_opc_imm(s, sw1, TCG_TMP3, base, 0);
+ tcg_out_opc_imm(s, sw2, TCG_TMP3, base, 3);
I'd keep the parity with ld_unalign and use 0 + 0, 0 + 3, ...
+ tcg_out_bswap32(s, TCG_TMP3, MIPS_BE ? hi : lo, 0);
+ tcg_out_opc_imm(s, sw1, TCG_TMP3, base, 4);
+ tcg_out_opc_imm(s, sw2, TCG_TMP3, base, 7);
4 + 0, 4 + 3, ...
+ break;
+ }
+ /* fall through */
+ case MO_64:
+ if (TCG_TARGET_REG_BITS == 64) {
+ tcg_out_opc_imm(s, sd1, lo, base, 0);
+ tcg_out_opc_imm(s, sd2, lo, base, 7);
Ditto, ...
+ } else {
+ tcg_out_opc_imm(s, sw1, MIPS_BE ? hi : lo, base, 0);
+ tcg_out_opc_imm(s, sw2, MIPS_BE ? hi : lo, base, 3);
+ tcg_out_opc_imm(s, sw1, MIPS_BE ? lo : hi, base, 4);
+ tcg_out_opc_imm(s, sw2, MIPS_BE ? lo : hi, base, 7);
Ditto.
+ }
+ break;
+
+ default:
+ tcg_abort();
+ }
+}
Beside the nitpicking comments, nothing to say, hardcore!
Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org>
