398 lines
7.1 KiB
C
398 lines
7.1 KiB
C
/* Copyright (c) Microsoft Corporation.
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Licensed under the MIT License. */
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/***************************************************************************
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This c file is compiled to a command-line exe which when run produces
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the 80386 asm version of the KCD2 decompression code.
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Register usage:
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eax: source bytes
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ebx: source address
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edi: destination address
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edx: working space
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ecx: for rep movsb
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esi: for rep movsb
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***************************************************************************/
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#include <stdio.h>
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#include "codkpri.h"
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#define kcbitMinMoveByDword 3
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typedef long bool;
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const bool fFalse = 0;
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const bool fTrue = 1;
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void Setup(void);
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void End(void);
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void Advance(long cb);
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void Test(long ibit);
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void Block(long ibit);
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void Literal(long ibit, bool fDword, bool fSingle);
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void Offset(long ibit, bool fDword, long cbit, long cbitOH, long dibBase,
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long cbBase);
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void Copy(long ibit, bool fDword);
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int main(void)
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{
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long ibit;
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Setup();
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for (ibit = 0; ibit < 8; ibit++)
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{
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if (kcbitMinMoveByDword <= kcbitMaxLenKcd2)
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{
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Literal(ibit, fTrue, fFalse);
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Offset(ibit, fTrue, kcbitKcd2_0, 2, kdibMinKcd2_0, 1);
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Offset(ibit, fTrue, kcbitKcd2_1, 3, kdibMinKcd2_1, 1);
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Offset(ibit, fTrue, kcbitKcd2_2, 4, kdibMinKcd2_2, 1);
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Offset(ibit, fTrue, kcbitKcd2_3, 4, kdibMinKcd2_3, 2);
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Copy(ibit, fTrue);
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printf(" jmp LBlock%d\n", ibit);
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}
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Literal(ibit, fFalse, fTrue);
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Literal(ibit, fFalse, fFalse);
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Offset(ibit, fFalse, kcbitKcd2_0, 2, kdibMinKcd2_0, 1);
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Offset(ibit, fFalse, kcbitKcd2_1, 3, kdibMinKcd2_1, 1);
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Offset(ibit, fFalse, kcbitKcd2_2, 4, kdibMinKcd2_2, 1);
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Offset(ibit, fFalse, kcbitKcd2_3, 4, kdibMinKcd2_3, 2);
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Copy(ibit, fFalse);
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Block(ibit);
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}
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End();
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return 0;
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}
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void Setup(void)
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{
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printf(
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" // Setup\n"
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" long cbTot;\n"
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" byte *pbLimDst = (byte *)pvDst + cbDst;\n"
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" byte *pbLimSrc = (byte *)pvSrc + cbSrc - kcbTailKcd2;\n\n"
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"__asm\n"
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" {\n"
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" mov edi,pvDst\n"
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" mov ebx,pvSrc\n"
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" inc ebx\n"
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);
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Advance(4);
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printf(" jmp LBlock0\n");
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}
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void Copy(long ibit, bool fDword)
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{
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if (fDword)
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printf("\n // Copy Dword %d\nLCopyDword%d:\n", ibit, ibit);
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else
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printf("\n // Copy Byte %d\nLCopyByte%d:\n", ibit, ibit);
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printf(
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"#ifdef SAFETY\n"
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" push edx\n"
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" lea edx,[edi+ecx]\n"
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" cmp edx,pbLimDst\n"
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" pop edx\n"
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" ja LFail\n"
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"#endif //SAFETY\n"
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);
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printf(
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" neg esi\n"
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" add esi,edi\n"
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);
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printf(
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"#ifdef SAFETY\n"
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" cmp esi,pvDst\n"
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" jb LFail\n"
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"#endif //SAFETY\n"
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);
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if (fDword)
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{
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printf(
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" mov edx,ecx\n"
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" shr ecx,2\n"
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" and edx,3\n"
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" rep movsd\n"
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" mov ecx,edx\n"
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" rep movsb\n"
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);
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}
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else
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printf(" rep movsb\n");
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}
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void End(void)
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{
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printf(
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"\nLDone:\n"
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" sub edi,pvDst\n"
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" mov cbTot,edi\n"
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" }\n\n"
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);
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}
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void Advance(long cb)
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{
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switch (cb)
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{
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case 0:
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break;
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case 1:
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printf(
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" mov eax,[ebx-3]\n"
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" inc ebx\n"
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);
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break;
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case 2:
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printf(
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" mov eax,[ebx-2]\n"
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" add ebx,2\n"
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);
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break;
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case 3:
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printf(
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" mov eax,[ebx-1]\n"
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" add ebx,3\n"
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);
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break;
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case 4:
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printf(
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" mov eax,[ebx]\n"
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" add ebx,4\n"
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);
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break;
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default:
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printf("*** BUG\n");
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break;
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}
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}
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void Test(long ibit)
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{
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if (ibit < 8)
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printf(" test al,%d\n", 1 << ibit);
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else if (ibit < 16)
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printf(" test ah,%d\n", 1 << (ibit - 8));
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else
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printf(" test eax,%d\n", 1 << ibit);
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}
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void Block(long ibit)
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{
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long cbit, ibitT;
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printf("\n // Block %d\n", ibit);
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printf("LBlock%d:\n", ibit);
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for (cbit = 0; cbit <= kcbitMaxLenKcd2; cbit++)
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{
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Test(ibit + cbit);
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printf(" jz LLen%d_%d\n", ibit, cbit);
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}
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printf(" jmp LDone\n");
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for (cbit = 0; cbit <= kcbitMaxLenKcd2; cbit++)
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{
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printf("LLen%d_%d:\n", ibit, cbit);
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if (cbit == 0)
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printf(" mov ecx,1\n");
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else
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{
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printf(" mov ecx,eax\n");
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printf(" shr ecx,%d\n", ibit + cbit + 1);
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printf(" and ecx,%d\n", (1 << cbit) - 1);
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printf(" or ecx,%d\n", (1 << cbit));
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}
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ibitT = ibit + cbit + cbit + 1;
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Advance(ibitT / 8);
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ibitT &= 0x07;
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Test(ibitT);
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if (cbit == 0)
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printf(" jz LLitSingle%d\n", ibitT);
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else if (cbit < kcbitMinMoveByDword)
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printf(" jz LLitByte%d\n", ibitT);
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else
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printf(" jz LLitDword%d\n", ibitT);
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Test(ibitT + 1);
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if (cbit < kcbitMinMoveByDword)
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{
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printf(" jz L%dBitOffByte%d\n", kcbitKcd2_0, ibitT);
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Test(ibitT + 2);
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printf(" jz L%dBitOffByte%d\n", kcbitKcd2_1, ibitT);
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Test(ibitT + 3);
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printf(" jz L%dBitOffByte%d\n", kcbitKcdc2, ibitT);
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printf(" jmp L%dBitOffByte%d\n", kcbitKcdc3, ibitT);
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}
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else
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{
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printf(" jz L%dBitOffDword%d\n", kcbitKcd2_0, ibitT);
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Test(ibitT + 2);
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printf(" jz L%dBitOffDword%d\n", kcbitKcd2_1, ibitT);
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Test(ibitT + 3);
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printf(" jz L%dBitOffDword%d\n", kcbitKcdc2, ibitT);
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printf(" jmp L%dBitOffDword%d\n", kcbitKcdc3, ibitT);
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}
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}
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}
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void Offset(long ibit, bool fDword, long cbit, long cbitOH, long dibBase,
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long cbBase)
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{
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ibit = (ibit - cbit - cbitOH) & 0x07;
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if (fDword)
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printf("\nL%dBitOffDword%d:\n", cbit, ibit);
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else
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printf("\nL%dBitOffByte%d:\n", cbit, ibit);
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printf(" mov esi,eax\n");
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if (cbBase == 1)
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printf(" inc ecx\n");
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else
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printf(" add ecx,%d\n", cbBase);
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printf(" shr esi,%d\n", ibit + cbitOH);
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printf(" and esi,%d\n", (1 << cbit) - 1);
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if (1 == dibBase)
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printf(" inc esi\n");
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else
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printf(" add esi,%d\n", dibBase);
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ibit += cbitOH + cbit;
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Advance(ibit / 8);
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ibit &= 0x07;
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if (fDword)
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{
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if (dibBase < 4 && fDword)
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{
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printf(" cmp esi,4\n");
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printf(" jb LCopyByte%d\n", ibit);
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}
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printf(" jmp LCopyDword%d\n", ibit);
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}
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else
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printf(" jmp LCopyByte%d\n", ibit);
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}
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void Literal(long ibit, bool fDword, bool fSingle)
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{
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ibit = (ibit - 1) & 0x07;
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if (fDword)
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printf("\nLLitDword%d:\n", ibit);
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else if (fSingle)
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printf("\nLLitSingle%d:\n", ibit);
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else
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printf("\nLLitByte%d:\n", ibit);
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ibit++;
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if (fSingle)
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{
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printf(
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"#ifdef SAFETY\n"
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" cmp edi,pbLimDst\n"
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" jae LFail\n"
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"#endif //SAFETY\n"
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);
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if (ibit == 8)
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{
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printf(
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" mov [edi],ah\n"
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" inc edi\n"
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);
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}
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else
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{
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printf(
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" mov edx,eax\n"
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" shr edx,%d\n"
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" mov [edi],dl\n"
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" inc edi\n"
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, ibit);
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}
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ibit += 8;
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Advance(ibit / 8);
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printf(" jmp LBlock%d\n", ibit & 0x07);
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return;
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}
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printf(
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"#ifdef SAFETY\n"
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" lea edx,[edi+ecx]\n"
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" cmp edx,pbLimDst\n"
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" ja LFail\n"
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"#endif //SAFETY\n"
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);
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if (ibit != 8)
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{
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// get the low bits of the last byte
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printf(" dec ecx\n");
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printf(" mov edx,eax\n");
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printf(" shr edx,%d\n", ibit);
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printf(" and edx,%d\n", (1 << (8 - ibit)) - 1);
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}
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printf(
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"#ifdef SAFETY\n"
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" lea esi,[ebx-3+ecx]\n"
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" cmp esi,pbLimSrc\n"
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" ja LFail\n"
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" sub esi,ecx\n"
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"#else //!SAFETY\n"
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" lea esi,[ebx-3]\n"
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"#endif //!SAFETY\n"
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);
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if (fDword)
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{
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printf(
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" mov eax,ecx\n"
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" shr ecx,2\n"
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" and eax,3\n"
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" rep movsd\n"
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" mov ecx,eax\n"
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" rep movsb\n"
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);
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}
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else
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printf(" rep movsb\n");
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printf(
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" lea ebx,[esi+4]\n"
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" mov eax,[esi]\n"
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);
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if (ibit != 8)
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{
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printf(" mov esi,eax\n");
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printf(" shl esi,%d\n", 8 - ibit);
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printf(
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" or edx,esi\n"
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" mov [edi],dl\n"
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" inc edi\n"
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);
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}
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printf(" jmp LBlock%d\n", ibit & 0x07);
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}
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