66 lines
No EOL
3.2 KiB
Text
66 lines
No EOL
3.2 KiB
Text
quit task is int 0x38
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yield task is int 0x39
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eax is cleared on yield
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syscall is int 0x30
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system call number in eax
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args in ebx, ecx, edx, esi, edi
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result in eax
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modifies ecx, edx
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modifies eax even if no value is returned
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see table 1
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file system calls have units of bytes unless otherwise specified
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functions returning handles or pointers use 0 to indicate error
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see keys.txt for the return type of the "get key" system call
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the edx register of "start task" is a pointer to a null-terminated string.
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a pointer to a readonly copy of this string is put into the new task's edx.
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invalid system call numbers change eax to -1, and have no other effect.
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table 1:
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function | eax | eax out | ebx | ecx | edx | esi | edi
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----------------|-----|-----------------|----------------|----------------|-------------|--------|-----
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open file | 0x0 | handle | drive number | path | | |
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close file | 0x1 | | handle | | | |
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file read | 0x2 | read | handle | file offset | count | buffer |
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get file size | 0x3 | size | handle | | | |
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start task | 0x4 | handle | drive number | path | passed sz | |
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log string | 0x5 | | sz string | | | |
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get key | 0x6 | keycode | | | | |
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allocate ram | 0x7 | start pointer | pages | | | |
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memory info | 0x8 | see table 2 | see table 2 | | | |
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wait for task | 0x9 | | handle | | | |
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enumerate dir | 0xa | count | drive number | path | see table 3 | max |
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vga print at | 0xb | | row << 8 | col | sz string | | |
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count of dir | 0xc | number of files | drive number | path | | |
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clear screen | 0xd | | | | | |
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set color | 0xe | | VGA color code | | | |
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swap color | 0xf | | row << 8 | col | | | |
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table 2:
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all values are in units of pages
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eax -1 indicates unrecognized ebx
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ebx | eax out
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-----|--------------------------
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0x0 | kernel dynamic area size
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0x1 | kernel dynamic area left
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0x2 | total userspace size
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0x3 | total userspace left
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0x4 | this process memory left
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table 3:
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edx of "enumerate dir" is a pointer to a buffer where an array of "directory info"s can be put.
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esi is the maximum number of "directory info"s to be placed in the buffer.
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the "directory info" structure is 128 bytes long. The first 100 bytes are a null-terminated string
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indicating the name of the file represented by this entry. The next four bytes are a 32-bit integer
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indicating the size of the file represented in bytes. The next byte's lowest bit is a one if this
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entry is a directory, and a zero if this entry is not. The remainder of the structure is reserved. |