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+/*
+ * Copyright 2004-2009 Analog Devices Inc.
+ *
+ * Licensed under the ADI BSD license or the GPL-2 (or later)
+ *
+ * 16 / 32 bit signed division.
+ * Special cases :
+ * 1) If(numerator == 0)
+ * return 0
+ * 2) If(denominator ==0)
+ * return positive max = 0x7fffffff
+ * 3) If(numerator == denominator)
+ * return 1
+ * 4) If(denominator ==1)
+ * return numerator
+ * 5) If(denominator == -1)
+ * return -numerator
+ *
+ * Operand : R0 - Numerator (i)
+ * R1 - Denominator (i)
+ * R0 - Quotient (o)
+ * Registers Used : R2-R7,P0-P2
+ *
+ */
+
+.global ___divsi3;
+.type ___divsi3, STT_FUNC;
+
+#ifdef CONFIG_ARITHMETIC_OPS_L1
+.section .l1.text
+#else
+.text
+#endif
+
+.align 2;
+___divsi3 :
+
+
+ R3 = R0 ^ R1;
+ R0 = ABS R0;
+
+ CC = V;
+
+ r3 = rot r3 by -1;
+ r1 = abs r1; /* now both positive, r3.30 means "negate result",
+ ** r3.31 means overflow, add one to result
+ */
+ cc = r0 < r1;
+ if cc jump .Lret_zero;
+ r2 = r1 >> 15;
+ cc = r2;
+ if cc jump .Lidents;
+ r2 = r1 << 16;
+ cc = r2 <= r0;
+ if cc jump .Lidents;
+
+ DIVS(R0, R1);
+ DIVQ(R0, R1);
+ DIVQ(R0, R1);
+ DIVQ(R0, R1);
+ DIVQ(R0, R1);
+ DIVQ(R0, R1);
+ DIVQ(R0, R1);
+ DIVQ(R0, R1);
+ DIVQ(R0, R1);
+ DIVQ(R0, R1);
+ DIVQ(R0, R1);
+ DIVQ(R0, R1);
+ DIVQ(R0, R1);
+ DIVQ(R0, R1);
+ DIVQ(R0, R1);
+ DIVQ(R0, R1);
+ DIVQ(R0, R1);
+
+ R0 = R0.L (Z);
+ r1 = r3 >> 31; /* add overflow issue back in */
+ r0 = r0 + r1;
+ r1 = -r0;
+ cc = bittst(r3, 30);
+ if cc r0 = r1;
+ RTS;
+
+/* Can't use the primitives. Test common identities.
+** If the identity is true, return the value in R2.
+*/
+
+.Lidents:
+ CC = R1 == 0; /* check for divide by zero */
+ IF CC JUMP .Lident_return;
+
+ CC = R0 == 0; /* check for division of zero */
+ IF CC JUMP .Lzero_return;
+
+ CC = R0 == R1; /* check for identical operands */
+ IF CC JUMP .Lident_return;
+
+ CC = R1 == 1; /* check for divide by 1 */
+ IF CC JUMP .Lident_return;
+
+ R2.L = ONES R1;
+ R2 = R2.L (Z);
+ CC = R2 == 1;
+ IF CC JUMP .Lpower_of_two;
+
+ /* Identities haven't helped either.
+ ** Perform the full division process.
+ */
+
+ P1 = 31; /* Set loop counter */
+
+ [--SP] = (R7:5); /* Push registers R5-R7 */
+ R2 = -R1;
+ [--SP] = R2;
+ R2 = R0 << 1; /* R2 lsw of dividend */
+ R6 = R0 ^ R1; /* Get sign */
+ R5 = R6 >> 31; /* Shift sign to LSB */
+
+ R0 = 0 ; /* Clear msw partial remainder */
+ R2 = R2 | R5; /* Shift quotient bit */
+ R6 = R0 ^ R1; /* Get new quotient bit */
+
+ LSETUP(.Llst,.Llend) LC0 = P1; /* Setup loop */
+.Llst: R7 = R2 >> 31; /* record copy of carry from R2 */
+ R2 = R2 << 1; /* Shift 64 bit dividend up by 1 bit */
+ R0 = R0 << 1 || R5 = [SP];
+ R0 = R0 | R7; /* and add carry */
+ CC = R6 < 0; /* Check quotient(AQ) */
+ /* we might be subtracting divisor (AQ==0) */
+ IF CC R5 = R1; /* or we might be adding divisor (AQ==1)*/
+ R0 = R0 + R5; /* do add or subtract, as indicated by AQ */
+ R6 = R0 ^ R1; /* Generate next quotient bit */
+ R5 = R6 >> 31;
+ /* Assume AQ==1, shift in zero */
+ BITTGL(R5,0); /* tweak AQ to be what we want to shift in */
+.Llend: R2 = R2 + R5; /* and then set shifted-in value to
+ ** tweaked AQ.
+ */
+ r1 = r3 >> 31;
+ r2 = r2 + r1;
+ cc = bittst(r3,30);
+ r0 = -r2;
+ if !cc r0 = r2;
+ SP += 4;
+ (R7:5)= [SP++]; /* Pop registers R6-R7 */
+ RTS;
+
+.Lident_return:
+ CC = R1 == 0; /* check for divide by zero => 0x7fffffff */
+ R2 = -1 (X);
+ R2 >>= 1;
+ IF CC JUMP .Ltrue_ident_return;
+
+ CC = R0 == R1; /* check for identical operands => 1 */
+ R2 = 1 (Z);
+ IF CC JUMP .Ltrue_ident_return;
+
+ R2 = R0; /* assume divide by 1 => numerator */
+ /*FALLTHRU*/
+
+.Ltrue_ident_return:
+ R0 = R2; /* Return an identity value */
+ R2 = -R2;
+ CC = bittst(R3,30);
+ IF CC R0 = R2;
+.Lzero_return:
+ RTS; /* ...including zero */
+
+.Lpower_of_two:
+ /* Y has a single bit set, which means it's a power of two.
+ ** That means we can perform the division just by shifting
+ ** X to the right the appropriate number of bits
+ */
+
+ /* signbits returns the number of sign bits, minus one.
+ ** 1=>30, 2=>29, ..., 0x40000000=>0. Which means we need
+ ** to shift right n-signbits spaces. It also means 0x80000000
+ ** is a special case, because that *also* gives a signbits of 0
+ */
+
+ R2 = R0 >> 31;
+ CC = R1 < 0;
+ IF CC JUMP .Ltrue_ident_return;
+
+ R1.l = SIGNBITS R1;
+ R1 = R1.L (Z);
+ R1 += -30;
+ R0 = LSHIFT R0 by R1.L;
+ r1 = r3 >> 31;
+ r0 = r0 + r1;
+ R2 = -R0; // negate result if necessary
+ CC = bittst(R3,30);
+ IF CC R0 = R2;
+ RTS;
+
+.Lret_zero:
+ R0 = 0;
+ RTS;
+
+.size ___divsi3, .-___divsi3