nivirx/stevia
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rough pass on fixing the stack across the board

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This commit is contained in:
Elaina Claus
2024-10-03 19:02:47 -04:00
parent 7fbb9b13e2
commit e03322b129
1 changed files with 46 additions and 112 deletions
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158
src/stage2/stage2.nasm
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@@ -103,32 +103,20 @@ main:
add sp, 0x2
; FAT Driver setup
push bp
mov bp, sp
call InitFATDriver
ERROR STEVIA_DEBUG_HALT
;
; Find first cluster of bootable file
;
push bp
mov bp, sp
call SearchFATDIR
PUSH_DWORD_EAX ; save return value of function as a 32-bit value on a 16-bit aligned stack
lea ax, [FileFound_OK_cstr]
push ax
call PrintString
add sp, 0x2
POP_DWORD_EAX ; return value of SearchFATDIR
push bp
mov bp, sp
PUSH_DWORD_EAX
call PrintDWORD
call PrintDWORD ; print 32bit value void PrintDWORD(uint32_t dword)
lea ax, [NewLine_cstr]
push ax
@@ -147,7 +135,6 @@ hcf:
;
; ###############
; TODO: fix the prolog, epilog and stack usage to confirm with cdecl16
InitFATDriver:
__CDECL16_ENTRY
.func:
@@ -192,7 +179,7 @@ InitFATDriver:
__CDECL16_EXIT
ret
; TODO: fix the prolog, epilog and stack usage to confirm with cdecl16
; TODO: needs validation
; load a file to the high memory buffer for the elf parser
; this involves using the low memory buffer for the bios call and moving the file sector by sector to high memory
;
@@ -204,18 +191,11 @@ InitFATDriver:
; halts/errors if file is not found
; uint32_t SearchFATDIR(uint8_t* SFN);
SearchFATDIR:
push di
push si
push bx
__CDECL16_ENTRY
.file_lookup:
xor ecx, ecx
xor edx, edx
.load_first_dir:
push bp
mov bp, sp
; uint8_t ReadFATCluster(uint16_t seg, uint16_t offset, uint32_t cluster)
mov eax, [fat32_ebpb + FAT32_ebpb_t.root_dir_cluster_32]
mov dword [fat32_state + FAT32_State_t.active_dir_cluster_32], eax
PUSH_DWORD_EAX
@@ -223,9 +203,9 @@ SearchFATDIR:
push ax ; offset
xor ax, ax
push ax ; segment
call ReadFATCluster ; uint8_t ReadFATCluster(uint16_t seg, uint16_t offset, uint32_t cluster)
add sp, 0x8
call ReadFATCluster
leave
lea si, [dir_buffer]
jmp SearchFATDIR.empty_dir_entry
@@ -233,13 +213,10 @@ SearchFATDIR:
; uint32_t NextCluster(uint32_t active_cluster);
; if eax >= 0x0FFFFFF8 then there are no more clusters (end of chain)
; if eax == 0x0FFFFFF7 then this is a cluster that is marked as bad
push bp
mov bp, sp
mov eax, dword [fat32_state + FAT32_State_t.active_dir_cluster_32]
PUSH_DWORD_EAX
call NextCluster
leave
add sp, 0x4
cmp eax, 0x0fff_fff7
jb SearchFATDIR.load_next_dir_next_OK
@@ -247,10 +224,6 @@ SearchFATDIR:
.load_next_dir_next_OK:
; load 512 bytes of directory entries from data sector
push bp
mov bp, sp
; uint8_t ReadFATCluster(uint16_t seg, uint16_t offset, uint32_t cluster)
mov eax, [fat32_state + FAT32_State_t.active_dir_cluster_32]
PUSH_DWORD_EAX
lea ax, [dir_buffer]
@@ -258,8 +231,8 @@ SearchFATDIR:
xor ax, ax
push ax ; segment
call ReadFATCluster
leave
call ReadFATCluster ; uint8_t ReadFATCluster(uint16_t seg, uint16_t offset, uint32_t cluster)
sub sp, 0x8
lea si, [dir_buffer]
.empty_dir_entry:
@@ -314,20 +287,15 @@ SearchFATDIR:
mov ax, [si + FAT32_SFN_t.cluster_16_low]
; eax == first cluster of file
.endp:
pop bx
pop si
pop di
__CDECL16_EXIT
ret
; TODO: fix the prolog, epilog and stack usage to confirm with cdecl16
; uint32_t NextCluster(uint32_t active_cluster);
; if eax >= 0x0FFFFFF8 then there are no more clusters (end of chain)
; if eax == 0x0FFFFFF7 then this is a cluster that is marked as bad
NextCluster:
push si
push di
push bx
__CDECL16_ENTRY
.func:
MOV_DWORD_EAX 2
mov edx, eax
mov si, fat32_nc_data
@@ -366,11 +334,7 @@ NextCluster:
add eax, ecx ; fat_sector + first_fat_sector
mov dword [si + FAT32_NextClusterData_t.fat_sector], eax
.load_fat_table:
; load correct fat
push bp
mov bp, sp
; uint8_t read_disk_raw(uint16_t buf_segment, uint16_t buf_offset, uint16_t lower_lower_lba, uint16_t upper_lower_lba)
; load correct fat
ror eax, 16
push ax
ror eax, 16
@@ -382,8 +346,9 @@ NextCluster:
xor ax, ax
push ax
; uint8_t read_disk_raw(uint16_t buf_segment, uint16_t buf_offset, uint16_t lower_lower_lba, uint16_t upper_lower_lba)
call read_disk_raw ; read_disk_raw(0, fat_buffer, 31:16 fat_sector, 15:0 fat_sector)
leave
add sp, 0x8
.read_cluster:
; next_cluster = fat_buffer[entry_offset]
@@ -391,17 +356,13 @@ NextCluster:
mov si, fat_buffer
mov eax, dword [bx+si+0]
.endp:
pop bx
pop di
pop si
__CDECL16_EXIT
ret
; TODO: fix the prolog, epilog and stack usage to confirm with cdecl16
; uint32_t ClusterToLBA(uint32_t cluster)
ClusterToLBA:
push si
push di
__CDECL16_ENTRY
.func:
MOV_DWORD_EAX 2
sub eax, 2
movzx edx, byte [fat32_bpb + FAT32_bpb_t.sectors_per_cluster_8]
@@ -409,54 +370,36 @@ ClusterToLBA:
add eax, dword [fat32_state + FAT32_State_t.first_data_sector_32]
; eax contains the LBA now
.endp:
pop di
pop si
__CDECL16_EXIT
ret
; TODO: fix the prolog, epilog and stack usage to confirm with cdecl16
; uint8_t ReadFATCluster(uint16_t seg, uint16_t offset, uint32_t cluster)
ReadFATCluster:
push si
push di
; cluster to LBA
MOV_DWORD_EAX 2
push bp
mov bp, sp
; uint32_t ClusterToLBA(uint32_t cluster)
__CDECL16_ENTRY
.func:
MOV_DWORD_EAX 8
PUSH_DWORD_EAX
call ClusterToLBA
leave ; eax == LBA
call ClusterToLBA ; uint32_t ClusterToLBA(uint32_t cluster)
add sp, 0x4 ; eax == LBA
mov dx, [bp-8] ; seg
mov dx, [bp + 4] ; seg
shl edx, 16
mov dx, [bp-6] ; offset
mov dx, [bp + 6] ; offset
; uint8_t read_disk_raw(uint16_t buf_segment, uint16_t buf_offset, uint16_t lower_lower_lba, uint16_t upper_lower_lba)
push bp
mov bp, sp
ror eax, 16
push ax
ror eax, 16
push ax
push ax ; uint32 cluster split to two (2) uint16_t's (lower and upper LBA)
push dx
push dx ; uint16_t buf_offset
ror edx, 16
push dx
;DEBUG_HCF
push dx ; unit16_t segment
call read_disk_raw
leave
add sp, 0x8
.endp:
pop di
pop si
__CDECL16_EXIT
ret
; ###############
@@ -489,14 +432,10 @@ ReadFATCluster:
; bp-6 = offset
; bp-8 = segment
; bp-10 = ret ptr
; TODO: fix the prolog, epilog and stack usage to confirm with cdecl16
; TODO: this needs validation
read_disk_raw:
push si
; uint8_t* kmemset(void* dest, uint8_t val, size_t len);
push bp
mov bp, sp
__CDECL16_ENTRY
.func:
mov ax, 0x10
push ax ; len = 16 bytes
xor ax, ax
@@ -504,21 +443,21 @@ read_disk_raw:
mov ax, lba_packet
push ax ; dest = lba_packet address
call kmemset
leave
call kmemset ; uint8_t* kmemset(void* dest, uint8_t val, size_t len);
add sp, 0x6
mov byte [lba_packet + LBAPkt_t.size], 0x10
mov word [lba_packet + LBAPkt_t.xfer_size], 0x0001
mov ax, [bp-2]
mov ax, [bp + 4]
shl eax, 16
mov ax, [bp-4]
mov ax, [bp + 6]
mov dword [lba_packet + LBAPkt_t.lower_lba], eax
mov ax, [bp-6]
mov ax, [bp + 8]
mov word [lba_packet + LBAPkt_t.offset], ax
mov ax, [bp-8]
mov ax, [bp + 10]
mov word [lba_packet + LBAPkt_t.segment], ax
mov si, lba_packet
@@ -527,9 +466,8 @@ read_disk_raw:
int 0x13
jnc read_disk_raw.endp
ERROR STAGE2_MBR_DISK_READ_ERROR
.endp:
pop si
__CDECL16_EXIT
ret
; Prints a C-Style string (null terminated) using BIOS vga teletype call
@@ -584,15 +522,14 @@ PrintCharacter:
; prints the hex representation of of val_upper:val_lower (4 byte value)
; void PrintDWORD(uint16_t val_upper, uint16_t val_lower);
PrintDWORD:
push si
__CDECL16_ENTRY
.func:
lea si, [IntToHex_table]
push bx
mov ebx, 16 ; base-16
mov ax, [bp-4] ; val_upper
mov ax, [bp + 6] ; val_upper
shl eax, 16
mov ax, [bp-2] ; val_lower
mov ax, [bp + 2] ; val_lower
xor edx, edx
xor cx, cx
@@ -618,12 +555,10 @@ PrintDWORD:
dec cx
push cx
push bp
mov bp, sp
movzx ax, byte [bx+si+0] ; bx = index into Hex lookup table
push ax
call PrintCharacter
leave
add sp, 0x2
pop cx
@@ -631,8 +566,7 @@ PrintDWORD:
jmp PrintDWORD.print_stack
.endp:
pop bx
pop si
__CDECL16_EXIT
ret
; Sets output to 80x25 16 color text mode via BIOS call