/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

// Implement shared vtbl methods.

#include "xptcprivate.h"

// The Linux/PPC ABI (aka PPC/SYSV ABI) passes the first 8 integral
// parameters and the first 8 floating point parameters in registers
// (r3-r10 and f1-f8), no stack space is allocated for these by the
// caller.  The rest of the parameters are passed in the callers stack
// area. The stack pointer has to retain 16-byte alignment, longlongs
// and doubles are aligned on 8-byte boundaries.

#define PARAM_BUFFER_COUNT     16
#define GPR_COUNT               8
#define FPR_COUNT               8

// PrepareAndDispatch() is called by SharedStub() and calls the actual method.
//
// - 'args[]' contains the arguments passed on stack
// - 'gprData[]' contains the arguments passed in integer registers
// - 'fprData[]' contains the arguments passed in floating point registers
// 
// The parameters are mapped into an array of type 'nsXPTCMiniVariant'
// and then the method gets called.

extern "C" nsresult ATTRIBUTE_USED
PrepareAndDispatch(nsXPTCStubBase* self,
                   uint32_t methodIndex,
                   uint32_t* args,
                   uint32_t *gprData,
                   double *fprData)
{
    nsXPTCMiniVariant paramBuffer[PARAM_BUFFER_COUNT];
    nsXPTCMiniVariant* dispatchParams = nullptr;
    nsIInterfaceInfo* iface_info = nullptr;
    const nsXPTMethodInfo* info;
    uint32_t paramCount;
    uint32_t i;
    nsresult result = NS_ERROR_FAILURE;

    NS_ASSERTION(self,"no self");

    self->GetInterfaceInfo(&iface_info);
    NS_ASSERTION(iface_info,"no interface info");
    if (! iface_info)
        return NS_ERROR_UNEXPECTED;

    iface_info->GetMethodInfo(uint16_t(methodIndex), &info);
    NS_ASSERTION(info,"no method info");
    if (! info)
        return NS_ERROR_UNEXPECTED;

    paramCount = info->GetParamCount();

    // setup variant array pointer
    if(paramCount > PARAM_BUFFER_COUNT)
        dispatchParams = new nsXPTCMiniVariant[paramCount];
    else
        dispatchParams = paramBuffer;

    NS_ASSERTION(dispatchParams,"no place for params");
    if (! dispatchParams)
        return NS_ERROR_OUT_OF_MEMORY;

    uint32_t* ap = args;
    uint32_t gpr = 1;    // skip one GPR register
    uint32_t fpr = 0;
    uint32_t tempu32;
    uint64_t tempu64;

    for(i = 0; i < paramCount; i++) {
        const nsXPTParamInfo& param = info->GetParam(i);
        const nsXPTType& type = param.GetType();
        nsXPTCMiniVariant* dp = &dispatchParams[i];
	
        if (!param.IsOut() && type == nsXPTType::T_DOUBLE) {
            if (fpr < FPR_COUNT)
                dp->val.d = fprData[fpr++];
            else {
                if ((uint32_t) ap & 4) ap++; // doubles are 8-byte aligned on stack
                dp->val.d = *(double*) ap;
                ap += 2;
		if (gpr < GPR_COUNT)
		    gpr += 2;
            }
            continue;
        }
        else if (!param.IsOut() && type == nsXPTType::T_FLOAT) {
            if (fpr < FPR_COUNT)
                dp->val.f = (float) fprData[fpr++]; // in registers floats are passed as doubles
            else {
                dp->val.f = *(float*) ap;
		ap += 1;
		if (gpr < GPR_COUNT)
		    gpr += 1;
            }
            continue;
        }
        else if (!param.IsOut() && (type == nsXPTType::T_I64
                                    || type == nsXPTType::T_U64)) {
            if (gpr & 1) gpr++; // longlongs are aligned in odd/even register pairs, eg. r5/r6
            if ((gpr + 1) < GPR_COUNT) {
                tempu64 = *(uint64_t*) &gprData[gpr];
                gpr += 2;
            }
            else {
                if ((uint32_t) ap & 4) ap++; // longlongs are 8-byte aligned on stack
                tempu64 = *(uint64_t*) ap;
                ap += 2;
            }
        }
        else {
            if (gpr < GPR_COUNT)
                tempu32 = gprData[gpr++];
            else
                tempu32 = *ap++;
        }

        if(param.IsOut() || !type.IsArithmetic()) {
            if (type == nsXPTType::T_JSVAL)
                dp->val.p = *((void**) tempu32);
            else
                dp->val.p = (void*) tempu32;
            continue;
        }

        switch(type) {
        case nsXPTType::T_I8:      dp->val.i8  = (int8_t)   tempu32; break;
        case nsXPTType::T_I16:     dp->val.i16 = (int16_t)  tempu32; break;
        case nsXPTType::T_I32:     dp->val.i32 = (int32_t)  tempu32; break;
        case nsXPTType::T_I64:     dp->val.i64 = (int64_t)  tempu64; break;
        case nsXPTType::T_U8:      dp->val.u8  = (uint8_t)  tempu32; break;
        case nsXPTType::T_U16:     dp->val.u16 = (uint16_t) tempu32; break;
        case nsXPTType::T_U32:     dp->val.u32 = (uint32_t) tempu32; break;
        case nsXPTType::T_U64:     dp->val.u64 = (uint64_t) tempu64; break;
        case nsXPTType::T_BOOL:    dp->val.b   = (bool)     tempu32; break;
        case nsXPTType::T_CHAR:    dp->val.c   = (char)     tempu32; break;
        case nsXPTType::T_WCHAR:   dp->val.wc  = (wchar_t)  tempu32; break;

        default:
            NS_ERROR("bad type");
            break;
        }
    }

    result = self->CallMethod((uint16_t) methodIndex, info, dispatchParams);

    NS_RELEASE(iface_info);

    if (dispatchParams != paramBuffer)
        delete [] dispatchParams;

    return result;
}

// Load r11 with the constant 'n' and branch to SharedStub().
//
// XXX Yes, it's ugly that we're relying on gcc's name-mangling here;
// however, it's quick, dirty, and'll break when the ABI changes on
// us, which is what we want ;-).

#define STUB_ENTRY(n)                                       \
__asm__ (                                                   \
        ".section \".text\" \n\t"                           \
        ".align 2 \n\t"                                     \
	".globl  Stub"#n"__14nsXPTCStubBase \n\t"           \
	".type   Stub"#n"__14nsXPTCStubBase,@function \n\n" \
                                                            \
"Stub"#n"__14nsXPTCStubBase: \n\t"                          \
	"li     11,"#n" \n\t"                               \
	"b      SharedStub@local \n"                        \
);

#define SENTINEL_ENTRY(n)                            \
nsresult nsXPTCStubBase::Sentinel##n()               \
{                                                    \
  NS_ERROR("nsXPTCStubBase::Sentinel called"); \
  return NS_ERROR_NOT_IMPLEMENTED;                   \
}

#include "xptcstubsdef.inc"
