os.h

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/*
Copyright 2020 Peter Howkins

Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef __OS_H__
#define __OS_H__

#include <string.h>
#include "stdint.h"


static inline void
oswrch(uint8_t a_char)
{
    __asm__ __volatile__("jsr $ffee" : : "Aq" (a_char));
}

static inline uint8_t
osrdch(void)
{
    uint8_t rega = 0;

    __asm__ __volatile__("jsr $ffe0" : "+Aq" (rega) );

    return rega;
}

static inline void
osnewl(void)
{
    __asm__ __volatile__("jsr $ffe7" : : : "a");
}

static inline void
osasci(uint8_t a_char)
{
    __asm__ __volatile__("jsr $ffe3" : : "Aq" (a_char));
}

static inline void
gsinit(uint8_t *a, uint8_t *y)
{
// TODO
}


static inline void
gsread(uint8_t *a, uint8_t *x, uint8_t y)
{
// TODO
}

extern uint8_t
osrdrm(uint8_t y_romnum, uintptr_t address);

static inline uint8_t
osrdsc(uintptr_t address)
{
// UNTESTED
    return osrdrm(0, address);
}

extern void
oswrsc(uint8_t a_byte, uintptr_t address);

static inline void
oseven(uint8_t y_eventnum)
{
// TODO
}

static inline void
oscli(char *xy_command)
{
    uint8_t regx = ((uintptr_t) xy_command) & 0xff;
    uint8_t regy = (((uintptr_t) xy_command) & 0xff00) >> 8;

    /* convert from C zero terminator to BBC OS terminator */
    xy_command[strlen(xy_command)] = 0x0d;

    __asm__ __volatile__("jsr $fff7" : : "xq"(regx), "yq"(regy) );
}

static inline void
osbyte(uint8_t a_func, uint8_t *x, uint8_t *y)
{
    uint8_t regx = *x;
    uint8_t regy = *y;

    __asm__ __volatile__("jsr $fff4" : "+xq"(regx), "+yq"(regy) : "Aq" (a_func));
    *x = regx;
    *y = regy;
}

extern void
osword(uint8_t a_func, const void *xy_pointer);

typedef struct osfile_parameterblock_s
{
    int32_t file_name:     16;  
    int32_t load_address:  32;  
    int32_t exec_address:  32;  
    int32_t start_address: 32;  
    int32_t end_address:   32;  
} osfile_parameterblock;

typedef enum osfile_action_e
{
    osfile_saveblock       = 0,
    osfile_writeinfo       = 1,
    osfile_writeload       = 2,
    osfile_writeexec       = 3,
    osfile_writeattr       = 4,
    osfile_readinfo        = 5,
    osfile_deletenamedfile = 6,
    osfile_loadnamedfile   = 0xff,
} osfile_action;

extern void
osfile(uint8_t a_action, const osfile_parameterblock *xy_pblock);

// TODO requires zero page access, how much does the C program mess with that?
// void osargs(uint8_t *a_action, uint8_t x_zp_poiner, uint8_t y_filehandle

static inline uint8_t
osbget(uint8_t y_handle)
{
    uint8_t rega = 0;

    __asm__ __volatile__("jsr $ffd7" : "+Aq" (rega) : "yq"(y_handle) );

    return rega;
}

static inline void
osbput(uint8_t a_byte, uint8_t y_handle)
{
    __asm__ __volatile__("jsr $ffd4" :  : "Aq" (a_byte), "yq"(y_handle) );
}

typedef struct osgbpb_controlblock_s
{
    int32_t file_handle: 8;   
    int32_t data_pointer: 32; 
    int32_t num_bytes: 32;    
    int32_t seq_pointer: 32;  
} osgbpb_controlblock;

typedef enum osgbpb_action_e
{
    osgbpb_putbytes_seq       = 1,
    osgbpb_putbytes           = 2,
    osgbpb_getbytes_seq       = 3,
    osgbpb_getbytes           = 4,
    osgbpb_gettitleandbootopt = 5,
    osgbpb_readdirectory      = 6,
    osgbpb_readlibrary        = 7,
    osgbpb_readfilenames      = 8
} osgbpb_action;

extern void
osgbpb(uint8_t a_action, const osgbpb_controlblock *xy_pblock);


extern uint8_t
osfind(uint8_t a_operation, uint8_t x, uint8_t y);

static inline uint8_t
osfind_open_r(char *filename)
{
    filename[strlen((filename))] = 0x0d;
    return osfind(0x40, ((uintptr_t) filename & 0xff), ((uintptr_t) filename & 0xff00) >> 8);
}

static inline uint8_t
osfind_open_w(char *filename)
{
    filename[strlen((filename))] = 0x0d;
    return osfind(0x80, ((uintptr_t) filename & 0xff), ((uintptr_t) filename & 0xff00) >> 8);
}

static inline uint8_t
osfind_open_rw(char *filename)
{
    filename[strlen((filename))] = 0x0d;
    return osfind(0xc0, ((uintptr_t) filename & 0xff), ((uintptr_t) filename & 0xff00) >> 8);
}

static inline void
osfind_close(uint8_t handle)
{
    osfind(0, 0, handle);
}


#endif // !__OS_H__