nivirx/stevia
1
0
Fork 0
Code Issues 1 Pull Requests Actions Packages Projects Releases 1 Wiki Activity

remove the dword stack macros and just use the 32bit override

Browse Source
This commit is contained in:
Elaina Claus
2024-10-05 10:13:18 -04:00
parent 6b2b1d2fc9
commit a0df1cb100
2 changed files with 31 additions and 95 deletions
Download Patch File Download Diff File Expand all files Collapse all files

82
src/stage2/stage2.nasm
View File

@@ -110,15 +110,17 @@ main:
; Find first cluster of bootable file
;
call SearchFATDIR
PUSH_DWORD_EAX ; save return value of function as a 32-bit value on a 16-bit aligned stack
push dword eax
lea ax, [FileFound_OK_cstr]
push ax
call PrintString
add sp, 0x2
call PrintDWORD ; print 32bit value void PrintDWORD(uint32_t dword)
push dword eax
call PrintDWORD ; void PrintDWORD(uint32_t dword)
add sp, 0x4
lea ax, [NewLine_cstr]
push ax
call PrintString
@@ -194,12 +196,11 @@ InitFATDriver:
SearchFATDIR:
__CDECL16_ENTRY
.file_lookup:
xor ecx, ecx
xor edx, edx
.load_first_dir:
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
push dword eax ; cluster
lea ax, [dir_buffer]
push ax ; offset
xor ax, ax
@@ -211,12 +212,11 @@ SearchFATDIR:
jmp SearchFATDIR.empty_dir_entry
.load_next_dir:
; 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
mov eax, dword [fat32_state + FAT32_State_t.active_dir_cluster_32]
PUSH_DWORD_EAX
call NextCluster
push dword eax
call NextCluster ; uint32_t NextCluster(uint32_t active_cluster);
add sp, 0x4
cmp eax, 0x0fff_fff7
@@ -226,12 +226,12 @@ SearchFATDIR:
.load_next_dir_next_OK:
; load 512 bytes of directory entries from data sector
mov eax, [fat32_state + FAT32_State_t.active_dir_cluster_32]
PUSH_DWORD_EAX
lea ax, [dir_buffer]
push dword eax
lea ax, [dir_buffer] ; cluster
push ax ; offset
xor ax, ax
push ax ; segment
call ReadFATCluster ; uint8_t ReadFATCluster(uint16_t seg, uint16_t offset, uint32_t cluster)
sub sp, 0x8
@@ -297,8 +297,7 @@ SearchFATDIR:
NextCluster:
__CDECL16_ENTRY
.func:
MOV_DWORD_EAX 2
mov edx, eax
mov dword edx, [bp + 4]
mov si, fat32_nc_data
.calc_offset:
; fat_offset = active_cluster * 4
@@ -336,19 +335,15 @@ NextCluster:
mov dword [si + FAT32_NextClusterData_t.fat_sector], eax
.load_fat_table:
; load correct fat
ror eax, 16
push ax
ror eax, 16
push ax
push dword eax
mov ax, fat_buffer
push ax
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)
call read_disk_raw ; read_disk_raw(0, fat_buffer, fat_sector)
add sp, 0x8
.read_cluster:
@@ -364,7 +359,7 @@ NextCluster:
ClusterToLBA:
__CDECL16_ENTRY
.func:
MOV_DWORD_EAX 2
mov dword eax, [bp + 4]
sub eax, 2
movzx edx, byte [fat32_bpb + FAT32_bpb_t.sectors_per_cluster_8]
mul edx
@@ -378,26 +373,21 @@ ClusterToLBA:
ReadFATCluster:
__CDECL16_ENTRY
.func:
MOV_DWORD_EAX 8
PUSH_DWORD_EAX
mov dword eax, [bp + 8]
push dword eax
call ClusterToLBA ; uint32_t ClusterToLBA(uint32_t cluster)
add sp, 0x4 ; eax == LBA
mov dx, [bp + 4] ; seg
shl edx, 16
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)
ror eax, 16
push ax
ror eax, 16
push ax ; uint32 cluster split to two (2) uint16_t's (lower and upper LBA)
push dword eax ;uint32_t lba
mov dx, [bp + 4] ; seg
push dx ; uint16_t buf_offset
ror edx, 16
mov dx, [bp + 6] ; offset
push dx ; unit16_t segment
call read_disk_raw
call read_disk_raw ; uint8_t read_disk_raw(uint16_t buf_segment, uint16_t buf_offset, uint32_t lba)
add sp, 0x8
.endp:
__CDECL16_EXIT
@@ -426,13 +416,7 @@ ReadFATCluster:
; successfully transferred
;
;
; uint8_t read_disk_raw(uint16_t buf_segment, uint16_t buf_offset, uint16_t lower_lower_lba, uint16_t upper_lower_lba)
; bp-0 = call frame
; bp-2 = upper_lower_lba
; bp-4 = lower_lower_lba
; bp-6 = offset
; bp-8 = segment
; bp-10 = ret ptr
; uint8_t read_disk_raw(uint16_t buf_segment, uint16_t buf_offset, uint32_t lba)
; TODO: this needs validation
read_disk_raw:
__CDECL16_ENTRY
@@ -450,15 +434,13 @@ read_disk_raw:
mov byte [lba_packet + LBAPkt_t.size], 0x10
mov word [lba_packet + LBAPkt_t.xfer_size], 0x0001
mov ax, [bp + 4]
shl eax, 16
mov ax, [bp + 6]
mov dword eax, [bp + 8]
mov dword [lba_packet + LBAPkt_t.lower_lba], eax
mov ax, [bp + 8]
mov ax, [bp + 6]
mov word [lba_packet + LBAPkt_t.offset], ax
mov ax, [bp + 10]
mov ax, [bp + 4]
mov word [lba_packet + LBAPkt_t.segment], ax
mov si, lba_packet
@@ -520,17 +502,15 @@ PrintCharacter:
ret
; TODO: fix the prolog, epilog and stack usage to confirm with cdecl16
; prints the hex representation of of val_upper:val_lower (4 byte value)
; void PrintDWORD(uint16_t val_upper, uint16_t val_lower);
; prints the hex representation of of val
; void PrintDWORD(uint32_t val);
PrintDWORD:
__CDECL16_ENTRY
.func:
lea si, [IntToHex_table]
mov ebx, 16 ; base-16
mov ax, [bp + 6] ; val_upper
shl eax, 16
mov ax, [bp + 2] ; val_lower
mov dword eax, [bp + 4] ;val
xor edx, edx
xor cx, cx