#include "compiler/StructMoves.h"
#include "compiler/CError.h"
#include "compiler/CParser.h"
#include "compiler/CodeGen.h"
#include "compiler/Operands.h"
#include "compiler/PCode.h"
#include "compiler/PCodeUtilities.h"
#include "compiler/Registers.h"

void make_addressable(Operand *opnd, SInt32 offset, int unusedArg) {
    int reg;

    if (opnd->optype == OpndType_IndirectSymbol)
        coerce_to_addressable(opnd);

    if (opnd->optype != OpndType_IndirectGPR_ImmOffset || (opnd->immOffset + offset) > 0x7FFF) {
        reg = used_virtual_registers[RegClass_GPR]++;
        load_address(reg, opnd);
        opnd->optype = OpndType_IndirectGPR_ImmOffset;
        opnd->reg = reg;
        opnd->object = NULL;
        opnd->immOffset = 0;
    }
}

static void load_displaced_address(Operand *opnd, SInt32 offset) {
    int reg;

    reg = used_virtual_registers[RegClass_GPR]++;
    if (opnd->optype == OpndType_IndirectSymbol)
        coerce_to_addressable(opnd);

    if (opnd->optype == OpndType_IndirectGPR_ImmOffset) {
        offset += opnd->immOffset;
        if (!FITS_IN_SHORT(offset)) {
            add_immediate(reg, opnd->reg, opnd->object, opnd->immOffset);
            emitpcode(PC_ADDI, reg, reg, 0, offset - opnd->immOffset);
        } else {
            add_immediate(reg, opnd->reg, opnd->object, offset);
        }
    } else if (opnd->optype == OpndType_IndirectGPR_Indexed) {
        emitpcode(PC_ADD, reg, opnd->reg, opnd->regOffset);
        emitpcode(PC_ADDI, reg, reg, 0, offset);
    } else {
        CError_FATAL(80);
    }

    opnd->optype = OpndType_IndirectGPR_ImmOffset;
    opnd->reg = reg;
    opnd->object = NULL;
    opnd->immOffset = 0;
}

static void move_block_via_load_store(Operand *dst, Operand *src, SInt32 len, SInt32 align) {
    SInt32 step;
    SInt32 pos;
    int floatReg;
    int reg;

    if (src->optype == OpndType_IndirectSymbol)
        coerce_to_addressable(src);
    if (dst->optype == OpndType_IndirectSymbol)
        coerce_to_addressable(dst);

    if (len == 8) {
        floatReg = used_virtual_registers[RegClass_FPR]++;
        if (src->optype == OpndType_IndirectGPR_ImmOffset) {
            load_store_register(PC_LFD, floatReg, src->reg, src->object, src->immOffset);
            setpcodeflags(src->flags);
        } else if (src->optype == OpndType_IndirectGPR_Indexed) {
            emitpcode(PC_LFDX, floatReg, src->reg, src->regOffset);
            setpcodeflags(src->flags);
        } else {
            CError_FATAL(145);
        }

        if (dst->optype == OpndType_IndirectGPR_ImmOffset) {
            load_store_register(PC_STFD, floatReg, dst->reg, dst->object, dst->immOffset);
            setpcodeflags(dst->flags);
        } else if (dst->optype == OpndType_IndirectGPR_Indexed) {
            emitpcode(PC_STFDX, floatReg, dst->reg, dst->regOffset);
            setpcodeflags(dst->flags);
        } else {
            CError_FATAL(157);
        }

        return;
    }

    if (copts.misaligned_mem_access == 0 && (UInt32) align < 4) {
        SInt32 tmp = (align == 0) ? 1 : (align > len) ? len : align;
        step = ((UInt32) tmp > 4) ? 4 : ((UInt32) tmp <= 2) ? (UInt32) tmp : 2;
    } else {
        step = ((UInt32) len > 4) ? 4 : ((UInt32) len <= 2) ? len : 2;
    }

    if (step != len) {
        if (dst->optype == OpndType_IndirectGPR_Indexed)
            make_addressable(dst, len, 0);
        if (src->optype == OpndType_IndirectGPR_Indexed)
            make_addressable(src, len, 0);
    }

    for (pos = 0; len != 0; len -= step, pos += step) {
        reg = used_virtual_registers[RegClass_GPR]++;
        if (src->optype == OpndType_IndirectGPR_ImmOffset) {
            load_store_register(
                (step == 1) ? PC_LBZ : (step == 2) ? PC_LHZ : PC_LWZ,
                reg,
                src->reg,
                src->object,
                src->immOffset + pos
                );
            setpcodeflags(src->flags);
        } else if (src->optype == OpndType_IndirectGPR_Indexed) {
            emitpcode(
                (step == 1) ? PC_LBZX : (step == 2) ? PC_LHZX : PC_LWZX,
                reg,
                src->reg,
                src->regOffset
                );
            setpcodeflags(src->flags);
        } else {
            CError_FATAL(183);
        }

        if (dst->optype == OpndType_IndirectGPR_ImmOffset) {
            load_store_register(
                (step == 1) ? PC_STB : (step == 2) ? PC_STH : PC_STW,
                reg,
                dst->reg,
                dst->object,
                dst->immOffset + pos
            );
            setpcodeflags(dst->flags);
        } else if (dst->optype == OpndType_IndirectGPR_Indexed) {
            emitpcode(
                (step == 1) ? PC_STBX : (step == 2) ? PC_STHX : PC_STWX,
                reg,
                dst->reg,
                dst->regOffset
            );
            setpcodeflags(dst->flags);
        } else {
            CError_FATAL(195);
        }
    }
}

static void move_block_via_load_store_sequence(Operand *dst, Operand *src, SInt32 len, SInt32 align) {
    SInt32 pos;
    int i;
    SInt32 step;

    pos = 0;
    make_addressable(dst, len, 0);
    make_addressable(src, len, 0);

    if ((align % 8) == 0) {
        while (len >= 16) {
            int reg1 = used_virtual_registers[RegClass_FPR]++;
            int reg2 = used_virtual_registers[RegClass_FPR]++;
            load_store_register(PC_LFD, reg1, src->reg, src->object, src->immOffset + pos);
            setpcodeflags(src->flags);
            load_store_register(PC_LFD, reg2, src->reg, src->object, src->immOffset + pos + 8);
            setpcodeflags(src->flags);

            load_store_register(PC_STFD, reg1, dst->reg, dst->object, dst->immOffset + pos);
            setpcodeflags(dst->flags);
            load_store_register(PC_STFD, reg2, dst->reg, dst->object, dst->immOffset + pos + 8);
            setpcodeflags(dst->flags);

            pos += 16;
            len -= 16;
        }
    }

    while (len >= 8) {
        if ((align % 8) == 0) {
            int reg = used_virtual_registers[RegClass_FPR]++;

            load_store_register(PC_LFD, reg, src->reg, src->object, src->immOffset + pos);
            setpcodeflags(src->flags);

            load_store_register(PC_STFD, reg, dst->reg, dst->object, dst->immOffset + pos);
            setpcodeflags(dst->flags);

            pos += 8;
            len -= 8;
        } else {
            if (copts.misaligned_mem_access == 0 && (UInt32) align < 4) {
                SInt32 tmp = (align == 0) ? 1 : (align > len) ? len : align;
                step = ((UInt32) tmp > 4) ? 4 : ((UInt32) tmp > 2) ? 2 : 1;
            } else {
                step = 4;
            }

            for (i = 0; i < 8; i += (step * 2)) {
                int reg1 = used_virtual_registers[RegClass_GPR]++;
                int reg2 = used_virtual_registers[RegClass_GPR]++;

                load_store_register(
                    (step == 1) ? PC_LBZ : (step == 2) ? PC_LHZ : PC_LWZ,
                    reg1,
                    src->reg,
                    src->object,
                    src->immOffset + pos
                );
                setpcodeflags(src->flags);

                load_store_register(
                    (step == 1) ? PC_LBZ : (step == 2) ? PC_LHZ : PC_LWZ,
                    reg2,
                    src->reg,
                    src->object,
                    src->immOffset + pos + step
                );
                setpcodeflags(src->flags);

                load_store_register(
                    (step == 1) ? PC_STB : (step == 2) ? PC_STH : PC_STW,
                    reg1,
                    dst->reg,
                    dst->object,
                    dst->immOffset + pos
                );
                setpcodeflags(dst->flags);

                load_store_register(
                    (step == 1) ? PC_STB : (step == 2) ? PC_STH : PC_STW,
                    reg2,
                    dst->reg,
                    dst->object,
                    dst->immOffset + pos + step
                );
                setpcodeflags(dst->flags);

                pos += (step * 2);
                len -= (step * 2);
            }
        }
    }

    while (len) {
        int reg;

        if (copts.misaligned_mem_access == 0 && (UInt32) align < 4) {
            SInt32 tmp = (align == 0) ? 1 : (align > len) ? len : align;
            step = ((UInt32) tmp > 4) ? 4 : ((UInt32) tmp <= 2) ? (UInt32) tmp : 2;
        } else {
            step = ((UInt32) len > 4) ? 4 : ((UInt32) len <= 2) ? len : 2;
        }

        reg = used_virtual_registers[RegClass_GPR]++;

        load_store_register(
            (step == 1) ? PC_LBZ : (step == 2) ? PC_LHZ : PC_LWZ,
            reg,
            src->reg,
            src->object,
            src->immOffset + pos
        );
        setpcodeflags(src->flags);

        load_store_register(
            (step == 1) ? PC_STB : (step == 2) ? PC_STH : PC_STW,
            reg,
            dst->reg,
            dst->object,
            dst->immOffset + pos
        );
        setpcodeflags(dst->flags);

        len -= step;
        pos += step;
    }
}

static void move_block_via_inline_loop(Operand *dst, Operand *src, SInt32 len, SInt32 align) {
    PCodeLabel *label; // r25
    SInt32 pos; // r25
    SInt32 step; // r24
    int reg1; // r22
    int reg2; // r23
    SInt32 remainder; // r23

    label = makepclabel();

    if (copts.misaligned_mem_access == 0 && (UInt32) align < 4) {
        SInt32 tmp = (align == 0) ? 1 : (align > len) ? len : align;
        step = ((UInt32) tmp > 4) ? 4 : ((UInt32) tmp <= 2) ? (UInt32) tmp : 2;
    } else {
        step = 4;
    }

    load_displaced_address(dst, -step);
    load_displaced_address(src, -step);

    CError_ASSERT(377, (len / step) != 0);

    reg1 = used_virtual_registers[RegClass_GPR]++;
    load_immediate(reg1, len / (step * 2));
    emitpcode(PC_MTCTR, reg1);
    branch_label(label);

    reg1 = used_virtual_registers[RegClass_GPR]++;
    reg2 = used_virtual_registers[RegClass_GPR]++;

    load_store_register(
        (step == 1) ? PC_LBZ : (step == 2) ? PC_LHZ : PC_LWZ,
        reg1,
        src->reg,
        NULL,
        step
    );
    setpcodeflags(src->flags);

    load_store_register(
        (step == 1) ? PC_LBZU : (step == 2) ? PC_LHZU : PC_LWZU,
        reg2,
        src->reg,
        NULL,
        step * 2
    );
    setpcodeflags(src->flags);

    load_store_register(
        (step == 1) ? PC_STB : (step == 2) ? PC_STH : PC_STW,
        reg1,
        dst->reg,
        NULL,
        step
    );
    setpcodeflags(dst->flags);

    load_store_register(
        (step == 1) ? PC_STBU : (step == 2) ? PC_STHU : PC_STWU,
        reg2,
        dst->reg,
        NULL,
        step * 2
    );
    setpcodeflags(dst->flags);

    branch_decrement_always(PC_BDNZ, label);

    for (remainder = len & 7, pos = step; remainder != 0; remainder -= step, pos += step) {
        int reg;

        if (copts.misaligned_mem_access == 0 && (UInt32) align < 4) {
            SInt32 tmp = (align == 0) ? 1 : (align > remainder) ? remainder : align;
            step = ((UInt32) tmp > 4) ? 4 : ((UInt32) tmp <= 2) ? (UInt32) tmp : 2;
        } else {
            step = ((UInt32) remainder > 4) ? 4 : ((UInt32) remainder <= 2) ? remainder : 2;
        }

        reg = used_virtual_registers[RegClass_GPR]++;

        load_store_register(
            (step == 1) ? PC_LBZ : (step == 2) ? PC_LHZ : PC_LWZ,
            reg,
            src->reg,
            NULL,
            pos
        );
        setpcodeflags(src->flags);

        load_store_register(
            (step == 1) ? PC_STB : (step == 2) ? PC_STH : PC_STW,
            reg,
            dst->reg,
            NULL,
            pos
        );
        setpcodeflags(dst->flags);
    }
}

void move_block(Operand *dst, Operand *src, SInt32 len, SInt32 align) {
    Operand myDst;

    myDst = *dst;

    CError_ASSERT(447, myDst.optype >= OpndType_IndirectGPR_ImmOffset);
    CError_ASSERT(449, src->optype >= OpndType_IndirectGPR_ImmOffset);

    if (len == 1 || len == 2 || len == 4)
        move_block_via_load_store(&myDst, src, len, align);
    else if (len == 8 && align == 8)
        move_block_via_load_store(&myDst, src, len, align);
    else if (len <= 16 || (copts.optimizesize == 0 && len <= 64))
        move_block_via_load_store_sequence(&myDst, src, len, align);
    else
        move_block_via_inline_loop(&myDst, src, len, align);
}

static void load_word_of_small_struct(short dstReg, short srcReg, Operand *opnd, SInt32 offset, SInt32 len, SInt32 align) {
    short tmpReg;
    short extra = 0;

    switch (len) {
        case 1:
            tmpReg = used_virtual_registers[RegClass_GPR]++;
            load_store_register(PC_LBZ, tmpReg, srcReg, opnd->object, offset);
            setpcodeflags(opnd->flags);
            emitpcode(PC_RLWINM, dstReg, tmpReg, 24, 0, 7);
            setpcodeflags(opnd->flags);
            break;
        case 2:
        case 3:
            if (align > 1) {
                tmpReg = used_virtual_registers[RegClass_GPR]++;
                load_store_register(PC_LHZ, tmpReg, srcReg, opnd->object, offset);
                extra += 2;
                setpcodeflags(opnd->flags);
                emitpcode(PC_RLWINM, dstReg, tmpReg, 16, 0, 15);
                setpcodeflags(opnd->flags);
            } else {
                tmpReg = used_virtual_registers[RegClass_GPR]++;
                load_store_register(PC_LBZ, tmpReg, srcReg, opnd->object, offset);
                setpcodeflags(opnd->flags);
                emitpcode(PC_RLWINM, dstReg, tmpReg, 24, 0, 7);
                setpcodeflags(opnd->flags);

                load_store_register(PC_LBZ, tmpReg, srcReg, opnd->object, offset + 1);
                extra += 2;
                setpcodeflags(opnd->flags);
                emitpcode(PC_RLWIMI, dstReg, tmpReg, 16, 8, 15);
                setpcodeflags(opnd->flags);
            }
            if (len == 3) {
                load_store_register(PC_LBZ, tmpReg, srcReg, opnd->object, offset + extra);
                setpcodeflags(opnd->flags);
                emitpcode(PC_RLWIMI, dstReg, tmpReg, 8, 16, 23);
                setpcodeflags(opnd->flags);
            }
            break;
        case 4:
            if (align > 2) {
                load_store_register(PC_LWZ, dstReg, srcReg, opnd->object, offset);
                setpcodeflags(opnd->flags);
            } else if (align > 1) {
                tmpReg = used_virtual_registers[RegClass_GPR]++;
                load_store_register(PC_LHZ, tmpReg, srcReg, opnd->object, offset);
                setpcodeflags(opnd->flags);
                emitpcode(PC_RLWINM, dstReg, tmpReg, 16, 0, 15);
                setpcodeflags(opnd->flags);

                load_store_register(PC_LHZ, tmpReg, srcReg, opnd->object, offset + 2);
                setpcodeflags(opnd->flags);
                emitpcode(PC_RLWIMI, dstReg, tmpReg, 0, 16, 31);
                setpcodeflags(opnd->flags);
            } else {
                tmpReg = used_virtual_registers[RegClass_GPR]++;
                load_store_register(PC_LBZ, tmpReg, srcReg, opnd->object, offset);
                setpcodeflags(opnd->flags);
                emitpcode(PC_RLWINM, dstReg, tmpReg, 24, 0, 7);
                setpcodeflags(opnd->flags);

                load_store_register(PC_LBZ, tmpReg, srcReg, opnd->object, offset + 1);
                setpcodeflags(opnd->flags);
                emitpcode(PC_RLWIMI, dstReg, tmpReg, 16, 8, 15);
                setpcodeflags(opnd->flags);

                load_store_register(PC_LBZ, tmpReg, srcReg, opnd->object, offset + 2);
                setpcodeflags(opnd->flags);
                emitpcode(PC_RLWIMI, dstReg, tmpReg, 8, 16, 23);
                setpcodeflags(opnd->flags);

                load_store_register(PC_LBZ, tmpReg, srcReg, opnd->object, offset + 3);
                setpcodeflags(opnd->flags);
                emitpcode(PC_RLWIMI, dstReg, tmpReg, 0, 24, 31);
                setpcodeflags(opnd->flags);
            }
            break;
    }
}

void load_small_block_into_reg(short dstReg, Operand *srcOpnd, Type *type, SInt32 align) {
    short finalReg;
    short tmpReg;
    SInt32 absAddress;

    coerce_to_addressable(srcOpnd);

    if (srcOpnd->optype == OpndType_IndirectGPR_Indexed) {
        CError_FATAL(557);

        tmpReg = used_virtual_registers[RegClass_GPR]++;
        load_address(tmpReg, srcOpnd);
        srcOpnd->optype = OpndType_IndirectGPR_ImmOffset;
        srcOpnd->reg = tmpReg;
        srcOpnd->object = NULL;
        srcOpnd->immOffset = 0;
    }

    if (copts.misaligned_mem_access)
        align = 4;

    switch (srcOpnd->optype) {
        case OpndType_GPRPair:
            return;
        case OpndType_GPR:
            return;
        case OpndType_GPR_ImmOffset:
            finalReg = dstReg ? dstReg : used_virtual_registers[RegClass_GPR]++;
            add_immediate(finalReg, srcOpnd->reg, srcOpnd->object, srcOpnd->immOffset);
            break;
        case OpndType_GPR_Indexed:
            finalReg = dstReg ? dstReg : used_virtual_registers[RegClass_GPR]++;
            emitpcode(PC_ADD, finalReg, srcOpnd->reg, srcOpnd->regOffset);
            break;
        case OpndType_Absolute:
            finalReg = dstReg ? dstReg : used_virtual_registers[RegClass_GPR]++;
            absAddress = srcOpnd->immediate;
            if (FITS_IN_SHORT(absAddress)) {
                emitpcode(PC_LI, finalReg, absAddress);
            } else {
                tmpReg = finalReg;
                if (copts.optimizationlevel > 1 && absAddress)
                    tmpReg = used_virtual_registers[RegClass_GPR]++;
                emitpcode(PC_LIS, tmpReg, 0, HIGH_PART(absAddress));
                if (absAddress)
                    emitpcode(PC_ADDI, finalReg, tmpReg, 0, LOW_PART(absAddress));
            }
            break;
        case OpndType_IndirectGPR_ImmOffset:
            finalReg = dstReg ? dstReg : used_virtual_registers[RegClass_GPR]++;
            load_word_of_small_struct(finalReg, srcOpnd->reg, srcOpnd, srcOpnd->immOffset, type->size, align);
            break;
        default:
            CError_FATAL(606);
    }

    srcOpnd->optype = OpndType_GPR;
    srcOpnd->reg = finalReg;
}

void load_small_block_into_reg_pair(short dstRegLo, short dstRegHi, Operand *srcOpnd, Type *type, SInt32 align) {
    short finalRegLo;
    short finalRegHi;
    short tmpRegLo;
    short tmpRegHi;
    short tmpReg;
    SInt32 absAddress;

    finalRegHi = -1;
    coerce_to_addressable(srcOpnd);

    if (srcOpnd->optype == OpndType_IndirectGPR_Indexed) {
        CError_FATAL(624);

        tmpReg = used_virtual_registers[RegClass_GPR]++;
        load_address(tmpReg, srcOpnd);
        srcOpnd->optype = OpndType_IndirectGPR_ImmOffset;
        srcOpnd->reg = tmpReg;
        srcOpnd->object = NULL;
        srcOpnd->immOffset = 0;
    }

    if (copts.misaligned_mem_access)
        align = 4;

    switch (srcOpnd->optype) {
        case OpndType_GPRPair:
            if (dstRegLo != 0 && dstRegHi == 0)
                dstRegHi = used_virtual_registers[RegClass_GPR]++;
            if (dstRegHi != 0 && dstRegLo == 0)
                dstRegLo = used_virtual_registers[RegClass_GPR]++;

            if (srcOpnd->reg != dstRegLo || srcOpnd->regHi != dstRegHi) {
                tmpRegLo = dstRegLo ? dstRegLo : srcOpnd->reg;
                tmpRegHi = dstRegHi ? dstRegHi : srcOpnd->regHi;

                if (tmpRegLo != srcOpnd->reg) {
                    if (tmpRegLo == srcOpnd->regHi) {
                        CError_ASSERT(657, tmpRegLo != tmpRegHi);
                        emitpcode(PC_MR, tmpRegHi, srcOpnd->regHi);
                        emitpcode(PC_MR, tmpRegLo, srcOpnd->reg);
                    } else {
                        emitpcode(PC_MR, tmpRegLo, srcOpnd->reg);
                        if (srcOpnd->regHi != tmpRegHi)
                            emitpcode(PC_MR, tmpRegHi, srcOpnd->regHi);
                    }
                } else if (tmpRegHi != srcOpnd->regHi) {
                    if (tmpRegHi == srcOpnd->reg) {
                        CError_ASSERT(671, tmpRegLo != tmpRegHi);
                        emitpcode(PC_MR, tmpRegLo, srcOpnd->reg);
                        emitpcode(PC_MR, tmpRegHi, srcOpnd->regHi);
                    } else {
                        emitpcode(PC_MR, tmpRegHi, srcOpnd->regHi);
                        if (srcOpnd->reg != tmpRegLo)
                            emitpcode(PC_MR, tmpRegLo, srcOpnd->reg);
                    }
                }
            }

            finalRegLo = srcOpnd->reg;
            finalRegHi = srcOpnd->regHi;
            break;
        case OpndType_GPR:
            CError_FATAL(688);
            break;
        case OpndType_GPR_ImmOffset:
            CError_FATAL(691);
            break;
        case OpndType_GPR_Indexed:
            CError_FATAL(694);
            break;
        case OpndType_Absolute:
            finalRegLo = dstRegLo ? dstRegLo : used_virtual_registers[RegClass_GPR]++;
            absAddress = srcOpnd->immediate;
            if (FITS_IN_SHORT(absAddress)) {
                emitpcode(PC_LI, finalRegLo, absAddress);
            } else {
                tmpReg = finalRegLo;
                if (copts.optimizationlevel > 1 && absAddress)
                    tmpReg = used_virtual_registers[RegClass_GPR]++;
                emitpcode(PC_LIS, tmpReg, 0, HIGH_PART(absAddress));
                if (absAddress)
                    emitpcode(PC_ADDI, finalRegLo, tmpReg, 0, LOW_PART(absAddress));
            }

            finalRegHi = dstRegHi ? dstRegHi : used_virtual_registers[RegClass_GPR]++;
            if (is_unsigned(type) || absAddress >= 0)
                load_immediate(finalRegHi, 0);
            else
                load_immediate(finalRegHi, -1);

            break;
        case OpndType_IndirectGPR_ImmOffset:
            finalRegLo = dstRegLo ? dstRegLo : used_virtual_registers[RegClass_GPR]++;
            finalRegHi = dstRegHi ? dstRegHi : used_virtual_registers[RegClass_GPR]++;
            if (srcOpnd->reg == finalRegHi) {
                if (srcOpnd->reg == finalRegLo) {
                    CError_FATAL(726);
                } else {
                    load_word_of_small_struct(
                        finalRegLo, srcOpnd->reg, srcOpnd,
                        srcOpnd->immOffset + low_offset, type->size - 4, align);
                    load_word_of_small_struct(
                        finalRegHi, srcOpnd->reg, srcOpnd,
                        srcOpnd->immOffset + high_offset, 4, align);
                }
            } else {
                load_word_of_small_struct(
                    finalRegHi, srcOpnd->reg, srcOpnd,
                    srcOpnd->immOffset + high_offset, 4, align);
                load_word_of_small_struct(
                    finalRegLo, srcOpnd->reg, srcOpnd,
                    srcOpnd->immOffset + low_offset, type->size - 4, align);
            }
            break;
        default:
            CError_FATAL(737);
    }

    if (finalRegHi == -1) {
        CError_FATAL(741);
    } else {
        srcOpnd->optype = OpndType_GPRPair;
        srcOpnd->reg = finalRegLo;
        srcOpnd->regHi = finalRegHi;
    }
}

static void store_word_of_small_struct(short srcReg, short dstReg, Operand *opnd, SInt32 offset, SInt32 len, SInt32 align) {
    short tmpReg;
    short extra = 0;

    switch (len) {
        case 1:
            tmpReg = used_virtual_registers[RegClass_GPR]++;
            emitpcode(PC_RLWINM, tmpReg, srcReg, 8, 24, 31);
            setpcodeflags(opnd->flags);
            load_store_register(PC_STB, tmpReg, dstReg, opnd->object, offset);
            setpcodeflags(opnd->flags);
            break;
        case 2:
        case 3:
            if (align > 1) {
                tmpReg = used_virtual_registers[RegClass_GPR]++;
                emitpcode(PC_RLWINM, tmpReg, srcReg, 16, 16, 31);
                setpcodeflags(opnd->flags);
                load_store_register(PC_STH, tmpReg, dstReg, opnd->object, offset);
                extra += 2;
                setpcodeflags(opnd->flags);
            } else {
                tmpReg = used_virtual_registers[RegClass_GPR]++;
                emitpcode(PC_RLWINM, tmpReg, srcReg, 8, 24, 31);
                setpcodeflags(opnd->flags);
                load_store_register(PC_STB, tmpReg, dstReg, opnd->object, offset);
                setpcodeflags(opnd->flags);

                emitpcode(PC_RLWINM, tmpReg, srcReg, 16, 24, 31);
                setpcodeflags(opnd->flags);
                load_store_register(PC_STB, tmpReg, dstReg, opnd->object, offset + 1);
                extra += 2;
                setpcodeflags(opnd->flags);
            }
            if (len == 3) {
                emitpcode(PC_RLWINM, tmpReg, srcReg, 24, 24, 31);
                setpcodeflags(opnd->flags);
                load_store_register(PC_STB, tmpReg, dstReg, opnd->object, offset + extra);
                setpcodeflags(opnd->flags);
            }
            break;
        case 4:
            if (align > 2) {
                load_store_register(PC_STW, srcReg, dstReg, opnd->object, offset);
                setpcodeflags(opnd->flags);
            } else if (align > 1) {
                tmpReg = used_virtual_registers[RegClass_GPR]++;
                emitpcode(PC_RLWINM, tmpReg, srcReg, 16, 16, 31);
                setpcodeflags(opnd->flags);
                load_store_register(PC_STH, tmpReg, dstReg, opnd->object, offset);
                setpcodeflags(opnd->flags);

                load_store_register(PC_STH, srcReg, dstReg, opnd->object, offset + 2);
                setpcodeflags(opnd->flags);
            } else {
                tmpReg = used_virtual_registers[RegClass_GPR]++;
                emitpcode(PC_RLWINM, tmpReg, srcReg, 8, 24, 31);
                setpcodeflags(opnd->flags);
                load_store_register(PC_STB, tmpReg, dstReg, opnd->object, offset);
                setpcodeflags(opnd->flags);

                emitpcode(PC_RLWINM, tmpReg, srcReg, 16, 24, 31);
                setpcodeflags(opnd->flags);
                load_store_register(PC_STB, tmpReg, dstReg, opnd->object, offset + 1);
                setpcodeflags(opnd->flags);

                emitpcode(PC_RLWINM, tmpReg, srcReg, 24, 24, 31);
                setpcodeflags(opnd->flags);
                load_store_register(PC_STB, tmpReg, dstReg, opnd->object, offset + 2);
                setpcodeflags(opnd->flags);

                load_store_register(PC_STB, srcReg, dstReg, opnd->object, offset + 3);
                setpcodeflags(opnd->flags);
            }
            break;
    }
}

void store_small_block_from_reg(short srcReg, Operand *dstOpnd, Type *type, SInt32 align) {
    short tmpReg;

    coerce_to_addressable(dstOpnd);

    if (dstOpnd->optype == OpndType_IndirectGPR_Indexed) {
        CError_FATAL(839);

        tmpReg = used_virtual_registers[RegClass_GPR]++;
        load_address(tmpReg, dstOpnd);
        dstOpnd->optype = OpndType_IndirectGPR_ImmOffset;
        dstOpnd->reg = tmpReg;
        dstOpnd->object = NULL;
        dstOpnd->immOffset = 0;
    }

    if (copts.misaligned_mem_access)
        align = 4;

    store_word_of_small_struct(srcReg, dstOpnd->reg, dstOpnd, dstOpnd->immOffset, type->size, align);
}

void store_small_block_from_reg_pair(short srcRegLo, short srcRegHi, Operand *dstOpnd, Type *type, SInt32 align) {
    short tmpReg;

    coerce_to_addressable(dstOpnd);

    if (dstOpnd->optype == OpndType_IndirectGPR_Indexed) {
        CError_FATAL(860);

        tmpReg = used_virtual_registers[RegClass_GPR]++;
        load_address(tmpReg, dstOpnd);
        dstOpnd->optype = OpndType_IndirectGPR_ImmOffset;
        dstOpnd->reg = tmpReg;
        dstOpnd->object = NULL;
        dstOpnd->immOffset = 0;
    }

    if (copts.misaligned_mem_access)
        align = 4;

    store_word_of_small_struct(
        srcRegLo, dstOpnd->reg, dstOpnd,
        dstOpnd->immOffset + low_offset, type->size - 4, align);
    store_word_of_small_struct(
        srcRegHi, dstOpnd->reg, dstOpnd,
        dstOpnd->immOffset + high_offset, 4, align);
}