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77 lines
1.5 KiB
77 lines
1.5 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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#include "libgcc.h" |
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;; This function also computes the remainder and stores it in er3. |
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.global __udivsi3 |
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__udivsi3: |
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mov.w A1E,A1E ; denominator top word 0? |
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bne DenHighNonZero |
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; do it the easy way, see page 107 in manual |
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mov.w A0E,A2 |
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extu.l A2P |
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divxu.w A1,A2P |
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mov.w A2E,A0E |
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divxu.w A1,A0P |
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mov.w A0E,A3 |
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mov.w A2,A0E |
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extu.l A3P |
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rts |
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; er0 = er0 / er1 |
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; er3 = er0 % er1 |
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; trashes er1 er2 |
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; expects er1 >= 2^16 |
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DenHighNonZero: |
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mov.l er0,er3 |
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mov.l er1,er2 |
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#ifdef CONFIG_CPU_H8300H |
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divmod_L21: |
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shlr.l er0 |
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shlr.l er2 ; make divisor < 2^16 |
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mov.w e2,e2 |
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bne divmod_L21 |
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#else |
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shlr.l #2,er2 ; make divisor < 2^16 |
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mov.w e2,e2 |
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beq divmod_L22A |
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divmod_L21: |
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shlr.l #2,er0 |
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divmod_L22: |
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shlr.l #2,er2 ; make divisor < 2^16 |
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mov.w e2,e2 |
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bne divmod_L21 |
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divmod_L22A: |
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rotxl.w r2 |
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bcs divmod_L23 |
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shlr.l er0 |
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bra divmod_L24 |
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divmod_L23: |
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rotxr.w r2 |
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shlr.l #2,er0 |
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divmod_L24: |
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#endif |
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;; At this point, |
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;; er0 contains shifted dividend |
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;; er1 contains divisor |
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;; er2 contains shifted divisor |
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;; er3 contains dividend, later remainder |
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divxu.w r2,er0 ; r0 now contains the approximate quotient (AQ) |
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extu.l er0 |
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beq divmod_L25 |
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subs #1,er0 ; er0 = AQ - 1 |
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mov.w e1,r2 |
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mulxu.w r0,er2 ; er2 = upper (AQ - 1) * divisor |
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sub.w r2,e3 ; dividend - 65536 * er2 |
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mov.w r1,r2 |
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mulxu.w r0,er2 ; compute er3 = remainder (tentative) |
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sub.l er2,er3 ; er3 = dividend - (AQ - 1) * divisor |
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divmod_L25: |
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cmp.l er1,er3 ; is divisor < remainder? |
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blo divmod_L26 |
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adds #1,er0 |
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sub.l er1,er3 ; correct the remainder |
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divmod_L26: |
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rts |
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.end
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