Hi,
On 2023/6/28 16:34, zhaotianrui wrote:
在 2023/6/28 上午11:42, Jinyang He 写道:
On 2023-06-26 16:47, Tianrui Zhao wrote:
[snip]
+ ldx.d t0, t1, t0
+ csrwr t0, LOONGARCH_CSR_PGDL
+
+ /* Mix GID and RID */
+ csrrd t1, LOONGARCH_CSR_GSTAT
+ bstrpick.w t1, t1, CSR_GSTAT_GID_SHIFT_END, CSR_GSTAT_GID_SHIFT
+ csrrd t0, LOONGARCH_CSR_GTLBC
+ bstrins.w t0, t1, CSR_GTLBC_TGID_SHIFT_END, CSR_GTLBC_TGID_SHIFT
+ csrwr t0, LOONGARCH_CSR_GTLBC
+
+ /*
+ * Switch to guest:
+ * GSTAT.PGM = 1, ERRCTL.ISERR = 0, TLBRPRMD.ISTLBR = 0
+ * ertn
+ */
+
+ /*
+ * Enable intr in root mode with future ertn so that host interrupt
+ * can be responsed during VM runs
+ * guest crmd comes from separate gcsr_CRMD register
+ */
+ ori t0, zero, CSR_PRMD_PIE
li.w t0, CSR_PRMD_PIE
Thanks for your advice, and I think it need not to replace it with
"li.w" there, as it has the same meaning with "ori" instruction, and
"ori" instruction is simple and clear enough. The same as the following
"move" instructions. What do you think of it.
Just my 2c: I'd agree that pseudo-instructions should be used wherever
possible and helping readability.
FYI there were similar usages way before, but all were cleaned up with
my previous commit 57ce5d3eefac ("LoongArch: Use the "move"
pseudo-instruction where applicable").
Such usages apparently came from an era when the LoongArch toolchains
didn't support any pseudo-instruction, and are less intuitive especially
for someone not familiar with LoongArch assembly. Given that familiarity
with LoongArch won't be widespread (unlike with e.g. RISC-V that are
adopted more widely), we should optimize for readability when writing
code; it's also a best practice in general because code is read way more
often than written, and people care about semantics not unnecessary
details like "how are moves like this or that materialized".
--
WANG "xen0n" Xuerui
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