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Merged
IanSeyler merged 4 commits into from
Mar 17, 2026
Merged

Add option for debug output #102

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a016128
Add debug flag for build.
IanSeyler Mar 17, 2026
74f8dac
Exclude strings on non-debug build
IanSeyler Mar 17, 2026
ed1f5c7
Binary size reductions
IanSeyler Mar 17, 2026
eb4761d
Build NOVIDEO as 4KiB binary
IanSeyler Mar 17, 2026
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1 change: 1 addition & 0 deletions src/interrupt.asm
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Original file line number Diff line number Diff line change
Expand Up @@ -55,6 +55,7 @@ spurious: ; handler for spurious interrupts

; -----------------------------------------------------------------------------
; CPU Exception Gates
align 16
exception_gate_00:
mov al, 0x00
jmp exception_gate_main
Expand Down
81 changes: 48 additions & 33 deletions src/pure64.asm
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Expand Up @@ -20,7 +20,11 @@
BITS 64
ORG 0x00008000
DEFAULT ABS
%ifdef NOVIDEO
PURE64SIZE equ 4096 ; Pad Pure64 to this length
%else
PURE64SIZE equ 6144 ; Pad Pure64 to this length
%endif

start:
jmp bootmode ; This command will be overwritten with 'NOP's before the AP's are started
Expand Down Expand Up @@ -268,10 +272,11 @@ start64:

; Configure serial port @ 0x03F8 as 115200 8N1
call init_serial


%ifdef DEBUG
mov rsi, msg_pure64 ; Output "[ Pure64 ]"
call debug_msg

; Output boot method
mov rsi, msg_boot
call debug_msg
Expand All @@ -284,6 +289,7 @@ boot_uefi:
mov rsi, msg_uefi
call debug_msg
msg_boot_done:
%endif

; Clear out the first 20KiB of memory. This will store the 64-bit IDT, GDT, PML4, PDP Low, and PDP High
mov ecx, 5120
Expand Down Expand Up @@ -385,7 +391,7 @@ skip1GB:
lgdt [GDTR64]

; Point cr3 at PML4
mov rax, 0x00002008 ; Write-thru enabled (Bit 3)
mov eax, 0x00002008 ; Write-thru enabled (Bit 3)
mov cr3, rax

xor eax, eax ; aka r0
Expand Down Expand Up @@ -429,9 +435,9 @@ clearcs64:
; Build the IDT
xor edi, edi ; create the 64-bit IDT (at linear address 0x0000000000000000)

mov rcx, 32
mov ecx, 32
make_exception_gates: ; make gates for exception handlers
mov rax, exception_gate
mov eax, exception_gate
push rax ; save the exception gate to the stack for later use
stosw ; store the low word (15:0) of the address
mov ax, SYS64_CODE_SEL
Expand All @@ -443,14 +449,14 @@ make_exception_gates: ; make gates for exception handlers
stosw ; store the high word (31:16) of the address
shr rax, 16
stosd ; store the extra high dword (63:32) of the address.
xor rax, rax
xor eax, eax
stosd ; reserved
dec rcx
dec ecx
jnz make_exception_gates

mov rcx, 256-32
mov ecx, 256-32
make_interrupt_gates: ; make gates for the other interrupts
mov rax, interrupt_gate
mov eax, interrupt_gate
push rax ; save the interrupt gate to the stack for later use
stosw ; store the low word (15:0) of the address
mov ax, SYS64_CODE_SEL
Expand All @@ -464,33 +470,22 @@ make_interrupt_gates: ; make gates for the other interrupts
stosd ; store the extra high dword (63:32) of the address.
xor eax, eax
stosd ; reserved
dec rcx
dec ecx
jnz make_interrupt_gates

; Set up the exception gates for all of the CPU exceptions
; The following code depends on exception gates being below 16MB
mov word [0x00*16], exception_gate_00 ; #DE
mov word [0x01*16], exception_gate_01 ; #DB
mov word [0x02*16], exception_gate_02
mov word [0x03*16], exception_gate_03 ; #BP
mov word [0x04*16], exception_gate_04 ; #OF
mov word [0x05*16], exception_gate_05 ; #BR
mov word [0x06*16], exception_gate_06 ; #UD
mov word [0x07*16], exception_gate_07 ; #NM
mov word [0x08*16], exception_gate_08 ; #DF
mov word [0x09*16], exception_gate_09 ; #MF
mov word [0x0A*16], exception_gate_10 ; #TS
mov word [0x0B*16], exception_gate_11 ; #NP
mov word [0x0C*16], exception_gate_12 ; #SS
mov word [0x0D*16], exception_gate_13 ; #GP
mov word [0x0E*16], exception_gate_14 ; #PF
mov word [0x0F*16], exception_gate_15
mov word [0x10*16], exception_gate_16 ; #MF
mov word [0x11*16], exception_gate_17 ; #AC
mov word [0x12*16], exception_gate_18 ; #MC
mov word [0x13*16], exception_gate_19 ; #XM
mov word [0x14*16], exception_gate_20 ; #VE
mov word [0x15*16], exception_gate_21 ; #CP
; The following code depends on:
; - Exception gates being below 16MB
; - Each exception_gate_XX being exactly 4 bytes apart
mov eax, exception_gate_00 ; Address of first handler
xor edi, edi ; Clear EDI as IDT starts at 0x0000
mov cl, 22 ; 22 exception gates (0x00-0x15)
set_exception_gate:
mov [rdi], ax ; Patch low word of handler address in IDT entry
add edi, 16 ; Advance to next IDT entry (16 bytes each)
add eax, 4 ; Advance to next gate handler (4 bytes each)
dec cl
jnz set_exception_gate

lidt [IDTR64] ; load IDT register

Expand Down Expand Up @@ -745,48 +740,64 @@ pde_end:
call debug_block
%endif

%ifdef DEBUG
mov rsi, msg_acpi
call debug_msg
%endif
call init_acpi ; Find and process the ACPI tables
%ifdef DEBUG
mov rsi, msg_ok
call debug_msg
%endif

%ifndef NOVIDEO
; Visual Debug (4/8)
mov ebx, 6
call debug_block
%endif

%ifdef DEBUG
mov rsi, msg_bsp
call debug_msg
%endif
call init_cpu ; Configure the BSP CPU
%ifdef DEBUG
mov rsi, msg_ok
call debug_msg
%endif

%ifndef NOVIDEO
; Visual Debug (5/8)
mov ebx, 8
call debug_block
%endif

%ifdef DEBUG
; Configure system timer
mov rsi, msg_timer
call debug_msg
%endif
call init_timer ; Configure the timer
%ifdef DEBUG
mov rsi, msg_ok
call debug_msg
%endif

%ifndef NOVIDEO
; Visual Debug (6/8)
mov ebx, 10
call debug_block
%endif

%ifdef DEBUG
mov rsi, msg_smp
call debug_msg
%endif
call init_smp ; Init of SMP, deactivate interrupts
%ifdef DEBUG
mov rsi, msg_ok
call debug_msg
%endif

; Reset the stack to the proper location (was set to 0x8000 previously)
mov rsi, [p_LocalAPICAddress] ; We would call p_smp_get_id here but the stack is not ...
Expand Down Expand Up @@ -945,8 +956,10 @@ lfb_wc_end:
call debug_block
%endif

%ifdef DEBUG
mov rsi, msg_kernel
call debug_msg
%endif

%ifdef FLOPPY
cmp byte [p_BootDisk], 'F' ; Check if sys is booted from floppy?
Expand Down Expand Up @@ -1073,6 +1086,7 @@ debug_progressbar:
%endif


%ifdef DEBUG
; -----------------------------------------------------------------------------
; debug_msg_char - Send a single char via the serial port
; IN: AL = Byte to send
Expand Down Expand Up @@ -1171,6 +1185,7 @@ debug_dump_al_l:
pop rax ; Restore RAX
ret
; -----------------------------------------------------------------------------
%endif


EOF:
Expand Down
2 changes: 2 additions & 0 deletions src/sysvar.asm
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@
; =============================================================================


%ifdef DEBUG
; Messages
msg_pure64: db 13, 10, 13, 10, '[ Pure64 ]', 0
msg_ok: db 'ok', 0
Expand All @@ -20,6 +21,7 @@ msg_bsp: db 13, 10, 'bsp ', 0
msg_timer: db 13, 10, 'timer ', 0
msg_smp: db 13, 10, 'smp ', 0
msg_kernel: db 13, 10, 'kernel start', 13, 10, 0
%endif

;CONFIG
cfg_smpinit: db 1 ; By default SMP is enabled. Set to 0 to disable.
Expand Down
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