Re: [Qemu-devel] [PATCH 3/4] tcg-hppa: Finish the port.

[Richard Henderson <rth@twiddle.net>]

On 03/17/2010 07:56 AM, Richard Henderson wrote:
> Since Aurelien's generic div/rem patch I could simply remove all
> that millicode stuff, including that tcg_reg_free, and let the
> generic code handle this instead.  Which would get to the same
> millicode routine via one or two extra levels of indirection.

The following patch implements this, and does indeed work.


r~

----

diff --git a/tcg/hppa/tcg-target.c b/tcg/hppa/tcg-target.c
index fe96779..c6ba593 100644
--- a/tcg/hppa/tcg-target.c
+++ b/tcg/hppa/tcg-target.c
@@ -193,11 +193,6 @@ static int target_parse_constraint(TCGArgConstraint *ct, const char **pct_str)
         ct->ct |= TCG_CT_REG;
         tcg_regset_set32(ct->u.regs, 0, 0xffffffff);
         break;
-    case 'c':
-        /* millicode division return register.  */
-        ct->ct | TCG_CT_REG;
-        tcg_regset_set32(ct->u.regs, 0, 1u << TCG_REG_RET1);
-        break;
     case 'L': /* qemu_ld/st constraint */
         ct->ct |= TCG_CT_REG;
         tcg_regset_set32(ct->u.regs, 0, 0xffffffff);
@@ -680,65 +675,6 @@ static void tcg_out_xmpyu(TCGContext *s, int retl, int reth,
     }
 }
 
-/* We define the following table directly in assembly so that we
-   can avoid getting PLABEL addresses.  */
-
-extern tcg_target_long qemu_milli[4];
-asm(".section .rodata\n\
-	.import $$divI,millicode\n\
-	.import $$remI,millicode\n\
-	.import $$divU,millicode\n\
-	.import $$remU,millicode\n\
-	.type	qemu_milli,@object\n\
-	.size	qemu_milli,16\n\
-qemu_milli:\n\
-	.word	$$divI\n\
-	.word	$$remI\n\
-	.word	$$divU\n\
-	.word	$$remU\n\
-	.previous");
-
-#define MILLI_DIVI	0
-#define MILLI_REMI	1
-#define MILLI_DIVU	2
-#define MILLI_REMU	3
-
-/* ??? Move this up in tcg.c.  */
-static void tcg_reg_free(TCGContext *, int);
-
-/* Note that the return is constrained to be r29, and the inputs are
-   constrained to not be in the first two parameter registers.  Otherwise,
-   we clobber r1 and r31, which are already marked as reserved.  */
-static void tcg_out_milli(TCGContext *s, int arg1, int arg2, int which)
-{
-    tcg_target_long routine, disp;
-
-    /* The parameter registers are clobbered.  Store them back to their
-       stack slots before we lose the contents.  */
-    tcg_reg_free(s, TCG_REG_R26);
-    tcg_reg_free(s, TCG_REG_R25);
-    tcg_out_mov(s, TCG_REG_R26, arg1);
-
-    routine = qemu_milli[which];
-    disp = (routine - ((tcg_target_long)s->code_ptr + 8)) >> 2;
-
-    if (check_fit_tl(disp, 17)) {
-        tcg_out32(s, INSN_BL | INSN_R2(TCG_REG_R31) | reassemble_17(disp));
-    } else {
-        uint32_t hi, lo;
-
-        hi = routine >> 11;
-        lo = routine & 0x7ff;
-
-        tcg_out32(s, INSN_LDIL | INSN_R2(TCG_REG_R1) | reassemble_21(hi));
-        tcg_out32(s, INSN_BLE_SR4 | INSN_R2(TCG_REG_R1)
-		  | reassemble_17(lo >> 2));
-    }
-
-    /* Second input copy in call delay slot.  */
-    tcg_out_mov(s, TCG_REG_R25, arg2);
-}
-
 static void tcg_out_branch(TCGContext *s, int label_index, int nul)
 {
     TCGLabel *l = &s->labels[label_index];
@@ -1443,19 +1379,6 @@ static inline void tcg_out_op(TCGContext *s, int opc, const TCGArg *args,
         tcg_out_xmpyu(s, args[0], args[1], args[2], args[3]);
         break;
 
-    case INDEX_op_div_i32:
-        tcg_out_milli(s, args[1], args[2], MILLI_DIVI);
-        break;
-    case INDEX_op_divu_i32:
-        tcg_out_milli(s, args[1], args[2], MILLI_DIVU);
-        break;
-    case INDEX_op_rem_i32:
-        tcg_out_milli(s, args[1], args[2], MILLI_REMI);
-        break;
-    case INDEX_op_remu_i32:
-        tcg_out_milli(s, args[1], args[2], MILLI_REMU);
-        break;
-
     case INDEX_op_bswap16_i32:
         tcg_out_bswap16(s, args[0], args[1], 0);
         break;
@@ -1590,11 +1513,6 @@ static const TCGTargetOpDef hppa_op_defs[] = {
     { INDEX_op_mul_i32, { "r", "r", "r" } },
     { INDEX_op_mulu2_i32, { "r", "r", "r", "r" } },
 
-    { INDEX_op_div_i32, { "c", "L", "L" } },
-    { INDEX_op_divu_i32, { "c", "L", "L" } },
-    { INDEX_op_rem_i32, { "c", "L", "L" } },
-    { INDEX_op_remu_i32, { "c", "L", "L" } },
-
     { INDEX_op_shl_i32, { "r", "r", "ri" } },
     { INDEX_op_shr_i32, { "r", "r", "ri" } },
     { INDEX_op_sar_i32, { "r", "r", "ri" } },
diff --git a/tcg/hppa/tcg-target.h b/tcg/hppa/tcg-target.h
index cd44deb..007aa7a 100644
--- a/tcg/hppa/tcg-target.h
+++ b/tcg/hppa/tcg-target.h
@@ -82,7 +82,7 @@ enum {
 #define TCG_TARGET_STACK_GROWSUP
 
 /* optional instructions */
-#define TCG_TARGET_HAS_div_i32
+// #define TCG_TARGET_HAS_div_i32
 #define TCG_TARGET_HAS_rot_i32
 #define TCG_TARGET_HAS_ext8s_i32
 #define TCG_TARGET_HAS_ext16s_i32