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prototyping

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This commit is contained in:
Elaina Claus
2025-09-17 20:59:48 -04:00
parent 831d45c33c
commit a3c9897291
1 changed files with 59 additions and 30 deletions
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89
include/fat32/FAT32_SYS.nasm
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@@ -19,6 +19,65 @@
%include "fat32/bpb_offset_bx.inc"
%include "fat32/fat32_structures.inc"
; what a 'mount' should probably do at this point...
; - read VBR at partition_lba
; - validate FAT32 signatures
; - fill fat32_bpb_t and compute derived fields
; - read FSInfo (free count/next free)
; - ???
; int fat32_mount(uint32_t partition_lba, fat32_bpb_t* out);
FAT32_mountfs:
__CDECL16_PROC_ENTRY
.proc:
; mount: parse BPB, derive fat0_lba, data_lba, cluster0_lba.
.endp:
__CDECL16_PROC_EXIT
ret
.error:
ERROR STEVIA_DEBUG_ERR
; int fat32_read_fat(const fat32_bpb_t* v, uint32_t clus, uint32_t* out);
FAT32_read_fat:
__CDECL16_PROC_ENTRY
.proc:
; Read 32-bit FAT entry for cluster n
.endp:
__CDECL16_PROC_EXIT
ret
.error:
ERROR STEVIA_DEBUG_ERR
; FAT32 entry is 32-bits; only low 28 bits are meaningful.
; EOC if (val & 0x0FFFFFFF) >= 0x0FFFFFF8.
; bad if == 0x0FFFFFF7.
; free if == 0x00000000.
; int fat32_next_clus(const fat32_bpb_t* v, uint32_t clus, uint32_t* out_next);
FAT32_next_cluster:
__CDECL16_PROC_ENTRY
.proc:
; Walk to next cluster in chain (validates EOC/bad)
.endp:
__CDECL16_PROC_EXIT
ret
.error:
ERROR STEVIA_DEBUG_ERR
; e.g:
; uint64_t clus_to_lba(const fat32_bpb_t* v, uint32_t clus) {
; return v->data_lba + (uint64_t)(clus - 2) * v->secs_per_clus;
; }
FAT32_clus_to_lba:
__CDECL16_PROC_ENTRY
.proc:
; Convert cluster -> LBA of first sector of that cluster
.endp:
__CDECL16_PROC_EXIT
ret
.error:
ERROR STEVIA_DEBUG_ERR
; Prototyping for now...
; TODO:
@@ -59,35 +118,6 @@
; int cache_read_sector(uint64_t lba, void* dst);
; int cache_invalidate_all(void);
; what a 'mount' should probably do at this point...
; - read VBR at partition_lba
; - validate FAT32 signatures
; - fill fat32_bpb_t and compute derived fields
; - read FSInfo (free count/next free)
; - ???
; int fat32_mount(uint32_t partition_lba, fat32_bpb_t* out);
;
; Accessors
;
; // Convert cluster -> LBA of first sector of that cluster
; uint64_t clus_to_lba(const fat32_bpb_t* v, uint32_t clus) {
; return v->data_lba + (uint64_t)(clus - 2) * v->secs_per_clus;
; }
; FAT32 entry is 32-bits; only low 28 bits are meaningful.
; EOC if (val & 0x0FFFFFFF) >= 0x0FFFFFF8.
; bad if == 0x0FFFFFF7.
; free if == 0x00000000.
; // Read 32-bit FAT entry for cluster n
; int fat32_read_fat(const fat32_bpb_t* v, uint32_t clus, uint32_t* out);
; // Walk to next cluster in chain (validates EOC/bad)
; int fat32_next_clus(const fat32_bpb_t* v, uint32_t clus, uint32_t* out_next);
;
; SFN directories
;
@@ -109,7 +139,6 @@
;int fat32_dir_iter_open(fat32_bpb_t* v, uint32_t first_clus, fat32_dir_iter_t* it);
;int fat32_dir_iter_next(fat32_dir_iter_t* it, fat32_dirent_sfn_t* out); // FS_OK or FS_E_END
; typedef struct {
; uint32_t first_clus;
; uint32_t size;