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target/sh4: mac.w: memory accesses are 16-bit words

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Before this change, executing a code sequence such as:

           mova   tblm,r0
           mov    r0,r1
           mova   tbln,r0
           clrs
           clrmac
           mac.w  @r0+,@r1+
           mac.w  @r0+,@r1+

           .align 4
  tblm:    .word  0x1234
           .word  0x5678
  tbln:    .word  0x9abc
           .word  0xdefg

Does not result in correct behavior:

Expected behavior:
  first macw : macl = 0x1234 * 0x9abc + 0x0
               mach = 0x0

  second macw: macl = 0x5678 * 0xdefg + 0xb00a630
               mach = 0x0

Observed behavior (qemu-sh4eb, prior to this commit):

  first macw : macl = 0x5678 * 0xdefg + 0x0
               mach = 0x0

  second macw: (unaligned longword memory access, SIGBUS)

Various SH-4 ISA manuals also confirm that `mac.w` is a 16-bit word memory
access, not a 32-bit longword memory access.

Signed-off-by: Zack Buhman <zack@buhman.org>
Reviewed-by: Yoshinori Sato <ysato@users.sourceforge.jp>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20240402093756.27466-1-zack@buhman.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Zack Buhman 2024-04-02 17:37:49 +08:00 committed by Richard Henderson
parent 26d937237f
commit b0f2f2976b
1 changed files with 2 additions and 2 deletions
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4
target/sh4/translate.c
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@ -816,10 +816,10 @@ static void _decode_opc(DisasContext * ctx)
TCGv arg0, arg1;
arg0 = tcg_temp_new();
tcg_gen_qemu_ld_i32(arg0, REG(B7_4), ctx->memidx,
MO_TESL | MO_ALIGN);
MO_TESW | MO_ALIGN);
arg1 = tcg_temp_new();
tcg_gen_qemu_ld_i32(arg1, REG(B11_8), ctx->memidx,
MO_TESL | MO_ALIGN);
MO_TESW | MO_ALIGN);
gen_helper_macw(tcg_env, arg0, arg1);
tcg_gen_addi_i32(REG(B11_8), REG(B11_8), 2);
tcg_gen_addi_i32(REG(B7_4), REG(B7_4), 2);