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ARM: Add integer variant of modulo operator.

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This commit is contained in:
Mike Pall 2011-04-16 23:29:57 +02:00
parent d636a3decd
commit add553edd8
1 changed files with 50 additions and 12 deletions
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62
src/buildvm_arm.dasc
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@ -1821,6 +1821,7 @@ static void build_subroutines(BuildCtx *ctx)
|->vm_trunc:
#endif
|
| // double lj_vm_mod(double dividend, double divisor);
|->vm_mod:
| push {r0, r1, r2, r3, r4, lr}
| bl extern __aeabi_ddiv
@ -1833,6 +1834,41 @@ static void build_subroutines(BuildCtx *ctx)
| add sp, sp, #20
| pop {pc}
|
| // int lj_vm_modi(int dividend, int divisor);
|->vm_modi:
| ands RB, CARG1, #0x80000000
| rsbmi CARG1, CARG1, #0 // a = |dividend|
| eor RB, RB, CARG2, asr #1 // Keep signdiff and sign(divisor).
| cmp CARG2, #0
| rsbmi CARG2, CARG2, #0 // b = |divisor|
| subs CARG4, CARG2, #1
| cmpne CARG1, CARG2
| moveq CARG1, #0 // if (b == 1 || a == b) a = 0
| tsthi CARG2, CARG4
| andeq CARG1, CARG1, CARG4 // else if ((b & (b-1)) == 0) a &= b-1
| bls >1
| // Use repeated subtraction to get the remainder.
| clz CARG3, CARG1
| clz CARG4, CARG2
| sub CARG4, CARG4, CARG3
| rsbs CARG3, CARG4, #31 // entry = (31-(clz(b)-clz(a)))*8
| addne pc, pc, CARG3, lsl #3 // Duff's device.
| nop
{
int i;
for (i = 31; i >= 0; i--) {
| cmp CARG1, CARG2, lsl #i
| subhs CARG1, CARG1, CARG2, lsl #i
}
}
|1:
| cmp CARG1, #0
| cmpne RB, #0
| submi CARG1, CARG1, CARG2 // if (y != 0 && signdiff) y = y - b
| eors CARG2, CARG1, RB, lsl #1
| rsbmi CARG1, CARG1, #0 // if (sign(divisor) != sign(y)) y = -y
| bx lr
|
|->vm_powi:
#if LJ_HASJIT
| NYI
@ -2266,33 +2302,42 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defop)
|
|.macro ins_arithdn, intins, fpcall
| ins_arithpre
|.if "intins" ~= "vm_modi"
| ins_next1
|.endif
| ins_arithcheck_int >5
|.if "intins" == "smull"
| smull CARG1, RC, CARG3, CARG1
| cmp RC, CARG1, asr #31
| ins_arithfallback bne
|.elif "intins" == "vm_modi"
| movs CARG2, CARG3
| ins_arithfallback beq
| bl ->vm_modi
| mvn CARG2, #~LJ_TISNUM
|.else
| intins CARG1, CARG1, CARG3
| ins_arithfallback bvs
|.endif
|4:
|.if "intins" == "vm_modi"
| ins_next1
|.endif
| ins_next2
| strd CARG12, [BASE, RA]
| ins_next3
|5: // FP variant.
| ins_arithfallback ins_arithcheck_num
| bl fpcall
|.if "intins" ~= "vm_modi"
| ins_next1
|.endif
| b <4
|.endmacro
|
|.macro ins_arithfp, fpcall
| ins_arithpre
| ins_arithfallback ins_arithcheck_num
||if (op == BC_MODVN) {
| ->BC_MODVN_Z:
||}
| bl fpcall
| ins_next1
| ins_next2
@ -2312,15 +2357,8 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defop)
case BC_DIVVN: case BC_DIVNV: case BC_DIVVV:
| ins_arithfp extern __aeabi_ddiv
break;
case BC_MODVN:
| // NYI: integer arithmetic.
| // Note: __aeabi_idivmod is unsuitable. It uses trunc, not floor.
| ins_arithfp ->vm_mod
break;
case BC_MODNV: case BC_MODVV:
| ins_arithpre
| ins_arithfallback ins_arithcheck_num
| b ->BC_MODVN_Z
case BC_MODVN: case BC_MODNV: case BC_MODVV:
| ins_arithdn vm_modi, ->vm_mod
break;
case BC_POW:
| // NYI: (partial) integer arithmetic.