emulate: save/restore host flags in fastop_dispatch #216
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OK to verify |
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emmm I'm investigating another interesting issue in PR#204 recently and finally came to the same root cause as described in this PR, that FLAGS are corrupted after fastop. |
core/emulate_ops.asm
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| @@ -210,11 +210,13 @@ fastop_dispatch: | |||
| mov reg_dst, [ebx] | |||
| mov reg_src1, [esi] | |||
| mov reg_src2, [edi] | |||
| pushf | |||
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I'll suggest move PUSHF to beginning, after push ebp. And move POPF to end, before pop ebp. Then change stack_arg(index) by adding another 0x4 offset. No need to change call stack_arg() so that the fastop handler and remaining arguments are still start from index 0.
core/emulate_ops.asm
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| @@ -237,11 +239,13 @@ fastop_dispatch: | |||
| mov reg_dst, [rsi] | |||
| mov reg_src1, [r10] | |||
| mov reg_src2, [r11] | |||
| pushf | |||
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Ditto. Move this PUSHF to beginning and adjust stack_arg() offset. Move POPF to end.
core/emulate_ops.asm
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| @@ -262,11 +266,13 @@ fastop_dispatch: | |||
| mov reg_dst, [r11] | |||
| mov reg_src1, [r8] | |||
| mov reg_src2, [r9] | |||
| pushf | |||
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Looks good to me! Thanks for the patch @jarveson, I also agree with the new |
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sure, so something like this then? |
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@jarveson would you mind update the commit message in your own branch? I'll merge it. |
fastop_dispatch isn't saving/restoring host flags before overwriting with guest flags, which can cause some interesting issues. This fixes that by just pushing and poping host flags before/after executing fastop instruction. Signed-off-by: Jake Arveson <jarveson@gmail.com>
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like this? otherwise im not fully sure what you mean |
Exactly. Unlike PR comments, detailed commit msg in original commit will remains in git repo which helps future development. |
fastop_dispatch isn't saving/restoring host flags before overwriting with guest flags, which can cause some interesting issues. This fixes that by just pushing and poping host flags before/after executing fastop instruction.