kvisc/vm/pc/mem.c

// The OS/K Team licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

#include <pc/arch.h>

ulong readmem(ctx_t *ctx, ulong addr, uint len)
{
    switch (len) {
        case 1: return readmem8(ctx, addr); break;
        case 2: return readmem16(ctx, addr); break;
        case 4: return readmem32(ctx, addr); break;
        case 8: return readmem64(ctx, addr); break;
        default: log("readmem() bad length!\n"); abort();
    }
}

void writemem(ctx_t *ctx, ulong val, ulong addr, uint len)
{
    switch (len) {
        case 1: writemem8(ctx, val, addr); break;
        case 2: writemem16(ctx, val, addr); break;
        case 4: writemem32(ctx, val, addr); break;
        case 8: writemem64(ctx, val, addr); break;
        default: log("writemem() bad length!\n"); abort();
    }
}

#define CHK_RANGE()                                                         \
    if (addr < MEMOFF || real >= MEMSIZE) {                                 \
        _except(ctx, E_ACC,                                                 \
            "Invalid MEM access: 0x%012lX (0x%012lX)", addr, real);         \
    }

#define CHK_ALIGN(type)                                                     \
    if (addr % alignof(type) > 0) {                                         \
        _except(ctx, E_ALI,                                                 \
            "Non-aligned memory access: 0x%012lX (0x%012lX) by %lu",        \
            addr, real, alignof(type));                                     \
    }

#define GETREAL()                                                           \
    addr += cr2;                                                            \
    ulong real = addr2real(addr)

ulong readmem8(ctx_t *ctx, ulong addr)
{
    GETREAL();
    CHK_RANGE();

    if (addr % 2 == 0) return (ulong)ctx->mp[real] & 0xFF;
    else return ((ulong)ctx->mp[real] & 0xFF00) >> 8;
}

ulong readmem16(ctx_t *ctx, ulong addr)
{
    GETREAL();
    CHK_RANGE();
    CHK_ALIGN(ushort);

    return (ulong)ctx->mp[real];
}

ulong readmem32(ctx_t *ctx, ulong addr)
{
    GETREAL();
    CHK_RANGE();
    CHK_ALIGN(uint);

    ulong val = ctx->mp[real++];
    val = val | ((ulong)ctx->mp[real] << 16);

    return val;
}

ulong readmem64(ctx_t *ctx, ulong addr)
{
    GETREAL();
    CHK_RANGE();
    CHK_ALIGN(ulong);

    ulong val = (ulong)ctx->mp[real++];
    val = val | ((ulong)ctx->mp[real++] << 16);
    val = val | ((ulong)ctx->mp[real++] << 32);
    val = val | ((ulong)ctx->mp[real] << 48);

    return val;
}

void writemem8(ctx_t *ctx, ulong val, ulong addr)
{
    GETREAL();
    CHK_RANGE();

    ushort v = ctx->mp[real];

    if (!(addr % 2)) {
        ctx->mp[real] = (v & 0xFF00) | (val & 0xFF);
    }

    else {
        ctx->mp[real] = (v & 0xFF) | (((val & 0xFF) << 8));
    }
}

void writemem16(ctx_t *ctx, ulong val, ulong addr)
{
    GETREAL();
    CHK_RANGE();
    CHK_ALIGN(ushort);

    ctx->mp[real] = val & 0xFFFF;
}

void writemem32(ctx_t *ctx, ulong val, ulong addr)
{
    GETREAL();
    CHK_RANGE();
    CHK_ALIGN(uint);

    ctx->mp[real++] = val & 0xFFFF;
    ctx->mp[real] = (val >> 16) & 0xFFFF;
}

void writemem64(ctx_t *ctx, ulong val, ulong addr)
{
    GETREAL();
    CHK_RANGE();
    CHK_ALIGN(ulong);

    ctx->mp[real++] = val;
    ctx->mp[real++] = (val >> 16) & 0xFFFF;
    ctx->mp[real++] = (val >> 32) & 0xFFFF;
    ctx->mp[real] = (val >> 48) & 0xFFFF;
}