diff options
Diffstat (limited to 'vds.h')
| -rw-r--r-- | vds.h | 61 |
1 files changed, 53 insertions, 8 deletions
@@ -24,7 +24,7 @@ #include <stdint.h> typedef unsigned char vdserr; -enum { +enum vds_errors { VDS_SUCCESSFUL = 0, VDS_REGION_NOT_CONTIGUOUS = 1, VDS_REGION_NOT_ALIGNED = 2, @@ -44,7 +44,7 @@ enum { VDS_FLAGS_NOT_SUPPORTED = 0x10, }; -enum { +enum vds_flags { /* Bit 1 = Automatically copy to/from buffer Bit 2 = Disable automatic buffer allocation @@ -62,7 +62,7 @@ enum { }; /** DMA Descriptor structure. Describes a potentially DMA-lockable buffer. */ -typedef _Packed struct VDS_DDS +typedef _Packed struct VDSDDS { /** Size of this buffer. */ uint32_t regionSize; @@ -74,7 +74,15 @@ typedef _Packed struct VDS_DDS uint16_t bufferId; /** Physical address of this buffer. */ uint32_t physicalAddress; -} VDS_DDS; +} VDSDDS; + +/** Converts a far pointer into equivalent linear address. + * Note that under protected mode linear != physical. + * That's what VDS is for. */ +static inline uint32_t vds_ptr_to_linear(const void __far * ptr) +{ + return ((uint32_t)(FP_SEG(ptr)) << 4) + FP_OFF(ptr); +} static bool vds_available(void); #pragma aux vds_available = \ @@ -89,9 +97,9 @@ static bool vds_available(void); /** Locks an already allocated buffer into a physical memory location. * regionSize, offset and segment must be valid in the DDS, * while the physical address is returned. */ -static vdserr vds_lock_dma_buffer_region(VDS_DDS __far * dds, unsigned char flags); +static vdserr vds_lock_dma_buffer_region(VDSDDS __far * dds, unsigned char flags); #pragma aux vds_lock_dma_buffer_region = \ - "stc" /* If nothing happens, assume failure. */ \ + "stc" \ "mov ax, 0x8103" \ "int 0x4B" \ "jc fail" \ @@ -99,14 +107,14 @@ static vdserr vds_lock_dma_buffer_region(VDS_DDS __far * dds, unsigned char flag "jmp end" \ "fail: test al, al" \ "jnz end" \ - "mov al, 0xFF" /* Force a error code if there was none. */ \ + "mov al, 0xFF" /* Force a error code if there was none. */ \ "end:" \ __parm [es di] [dx] \ __value [al] \ __modify [ax] /** Unlocks a locked buffer. */ -static vdserr vds_unlock_dma_buffer_region(VDS_DDS __far * dds, unsigned char flags); +static vdserr vds_unlock_dma_buffer_region(VDSDDS __far * dds, unsigned char flags); #pragma aux vds_unlock_dma_buffer_region = \ "stc" \ "mov ax, 0x8104" \ @@ -122,4 +130,41 @@ static vdserr vds_unlock_dma_buffer_region(VDS_DDS __far * dds, unsigned char fl __value [al] \ __modify [ax] +/** Allocates a DMA buffer. + * @param dds regionSize must be valid. + * @return dds Physical_Address, Buffer_ID, and Region_Size + */ +static vdserr vds_request_dma_buffer(VDSDDS __far * dds, unsigned char flags); +#pragma aux vds_request_dma_buffer = \ + "stc" \ + "mov ax, 0x8107" \ + "int 0x4B" \ + "jc fail" \ + "mov al, 0" \ + "jmp end" \ + "fail: test al, al" \ + "jnz end" \ + "mov al, 0xFF" \ + "end:" \ + __parm [es di] [dx] \ + __value [al] \ + __modify [ax] + +/** Frees a DMA buffer. */ +static vdserr vds_release_dma_buffer(VDSDDS __far * dds, unsigned char flags); +#pragma aux vds_release_dma_buffer = \ + "stc" \ + "mov ax, 0x8108" \ + "int 0x4B" \ + "jc fail" \ + "mov al, 0" \ + "jmp end" \ + "fail: test al, al" \ + "jnz end" \ + "mov al, 0xFF" \ + "end:" \ + __parm [es di] [dx] \ + __value [al] \ + __modify [ax] + #endif |