@@ -329,11 +329,6 @@ static const uint8_t tcg_cond_to_arm_cond[] = {
[TCG_COND_GTU] = COND_HI,
};
-static inline void tcg_out_bx(TCGContext *s, int cond, int rn)
-{
- tcg_out32(s, (cond << 28) | 0x012fff10 | rn);
-}
-
static inline void tcg_out_b(TCGContext *s, int cond, int32_t offset)
{
tcg_out32(s, (cond << 28) | 0x0a000000 |
@@ -402,6 +397,18 @@ static inline void tcg_out_mov_reg(TCGContext *s, int cond, int rd, int rm)
}
}
+static inline void tcg_out_bx(TCGContext *s, int cond, TCGReg rn)
+{
+ /* Unless the C portion of QEMU is compiled as thumb, we don't
+ actually need true BX semantics; merely a branch to an address
+ held in a register. */
+ if (use_armv5t_instructions) {
+ tcg_out32(s, (cond << 28) | 0x012fff10 | rn);
+ } else {
+ tcg_out_mov_reg(s, cond, TCG_REG_PC, rn);
+ }
+}
+
static inline void tcg_out_dat_imm(TCGContext *s,
int cond, int opc, int rd, int rn, int im)
{
@@ -977,7 +984,7 @@ static inline void tcg_out_st8(TCGContext *s, int cond,
* with the code buffer limited to 16MB we wouldn't need the long case.
* But we also use it for the tail-call to the qemu_ld/st helpers, which does.
*/
-static inline void tcg_out_goto(TCGContext *s, int cond, tcg_insn_unit *addr)
+static void tcg_out_goto(TCGContext *s, int cond, tcg_insn_unit *addr)
{
intptr_t addri = (intptr_t)addr;
ptrdiff_t disp = tcg_pcrel_diff(s, addr);
@@ -987,15 +994,9 @@ static inline void tcg_out_goto(TCGContext *s, int cond, tcg_insn_unit *addr)
return;
}
+ assert(use_armv5t_instructions || (addri & 1) == 0);
tcg_out_movi32(s, cond, TCG_REG_TMP, addri);
- if (use_armv5t_instructions) {
- tcg_out_bx(s, cond, TCG_REG_TMP);
- } else {
- if (addri & 1) {
- tcg_abort();
- }
- tcg_out_mov_reg(s, cond, TCG_REG_PC, TCG_REG_TMP);
- }
+ tcg_out_bx(s, cond, TCG_REG_TMP);
}
/* The call case is mostly used for helpers - so it's not unreasonable
In theory this would re-enable usage of QEMU on an armv4 host. Whether this is worthwhile is debatable -- we've been unconditionally issuing the armv5t BX instruction in the prologue since 2011 without complaint. Possibly we should simply require an armv6 host. Signed-off-by: Richard Henderson <rth@twiddle.net> --- tcg/arm/tcg-target.inc.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-)