37 lines
No EOL
1.7 KiB
Text
37 lines
No EOL
1.7 KiB
Text
.load 0x0000 ## BIOS is mapped to address 0x0000 in memory
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.entry _bios_entry_point
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.fixed 4096, 0xFF ## BIOS Needs to be 4096 Bytes exactly
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@include <data.dss>
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@include <utils.dss>
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@include <drivers.dss>
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@include <display.dss>
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## ============================= BIOS Program =============================
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.code
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_bios_entry_point:
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movb [VGA_Registers.VIDEO_MODE], VGA_VideoModes.TEXT_SINGLE_COLOR ## Enable Text_Single_Color graphics mode
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mov FL, 0b0000000000000001 ## Zero the FL Register and enable interrupts
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mov reg(S_REG_OFFSET), 0x0000 ## Zero the offset register
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movb [{MemoryAddresses.INT_VEC + (0x20 * 3)}], 0xFF ## Setting up int 0x20 handler
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mov [{MemoryAddresses.INT_VEC + (0x20 * 3) + 1}], $_int_20_handler ## --
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mov R10, 0x00 ## Setting up int 0x30 handler by using int 0x20 functionality
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mov R9, $_int_30_handler ## -Passing the handler's address
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mov R8, 0x30 ## -Passing the interrupt's code to setup
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int 0x20 ## -Calling int 0x20 with 0x00 as parameter, to set new handler up
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push 0
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call $_print_machine_info_signle_color ## Print BIOS logo and machine info
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## MBR Loading
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zflg Flags.InterruptsEnabled ## Disable interrupts
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push 0
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call $_load_mbr_data_block
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sflg Flags.InterruptsEnabled ## Enable interrupts
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## ----
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%low INST_BIOS_NODE_TOGGLE 0x00 ## Disable BIOS Mode before leaving the BIOS
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jmp MemoryAddresses.MBR ## Jump to start of MBR in memory
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hlt ## Just in case somehow execution reaches this point
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## ======================================================================== |