On 7/26/21 1:56 AM, Song Gao wrote:
Hi, Richard.
On 07/23/2021 08:46 AM, Richard Henderson wrote:
On 7/20/21 11:53 PM, Song Gao wrote:
+/* Fixed point arithmetic operation instruction translation */
+static bool trans_add_w(DisasContext *ctx, arg_add_w *a)
+{
+ TCGv Rd = cpu_gpr[a->rd];
+ TCGv Rj = cpu_gpr[a->rj];
+ TCGv Rk = cpu_gpr[a->rk];
+
+ if (a->rd == 0) {
+ /* Nop */
+ return true;
+ }
+
+ if (a->rj != 0 && a->rk != 0) {
+ tcg_gen_add_tl(Rd, Rj, Rk);
+ tcg_gen_ext32s_tl(Rd, Rd);
+ } else if (a->rj == 0 && a->rk != 0) {
+ tcg_gen_mov_tl(Rd, Rk);
+ } else if (a->rj != 0 && a->rk == 0) {
+ tcg_gen_mov_tl(Rd, Rj);
+ } else {
+ tcg_gen_movi_tl(Rd, 0);
+ }
+
+ return true;
+}
Do not do all of this "if reg(n) zero" testing.
Use a common function to perform the gpr lookup, and a small callback function
for the operation. Often, the callback function already exists within
include/tcg/tcg-op.h.
Please see my riscv cleanup patch set I referenced vs patch 6.
I am not sure that 'riscv cleanup' patchs at:
https://patchew.org/QEMU/20210709042608.883256-1-richard.hender...@linaro.org
It seems that gpr_dst/gpr_src are common function to perform the gpr lookup.
is that right?
More than that. The gen_arith() function, for example, performs all of the bookkeeping
for a binary operation.
For example,
static bool gen_arith(DisasContext *ctx, arg_fmt_rdrjrk *a,
void (*func)(TCGv, TCGv, TCGv))
{
TCGv dest = gpr_dst(ctx, a->rd);
TCGv src1 = gpr_src(ctx, a->rj);
TCGv src2 = gpr_src(ctx, a->rk);
func(dest, src1, src2);
return true;
}
#define TRANS(NAME, FUNC, ...) \
static bool trans_##NAME(DisasContext *ctx, arg_##NAME *a) \
{ return FUNC(ctx, a, __VA_ARGS__); }
static void gen_add_w(TCGv dest, TCGv src1, TCGv src2)
{
tcg_gen_add_tl(dest, src1, src2);
tcg_gen_ext32s_tl(dest, dest);
}
TRANS(add_w, gen_arith, gen_add_w)
TRANS(add_d, gen_arith, tcg_gen_add_tl)
r~
