commit 6819e313c8d799ab4f54feb2cbb6f3c1d91a07ea Author: pjht Date: Tue Mar 19 09:23:21 2024 -0500 Initial commit diff --git a/Tupfile b/Tupfile new file mode 100644 index 0000000..23bb6a6 --- /dev/null +++ b/Tupfile @@ -0,0 +1,7 @@ +.gitignore + +LDFLAGS = -z max-page-size=4096 --orphan-handling=error -T proglink.ld +ASFLAGS = -m68010 -spaces -Felf -ldots -align -quiet -x -nowarn=62 + +: foreach *.68k | ../ |> vasmm68k_mot $(ASFLAGS) -I../sysroot/usr/include -o %o %f |> %B.o +: *.o | proglink.ld ../ |> m68k-elf-ld $(LDFLAGS) -o %o %f '%' |> init diff --git a/cards.68k b/cards.68k new file mode 100644 index 0000000..abd5bd3 --- /dev/null +++ b/cards.68k @@ -0,0 +1,51 @@ + include syscalls.i + section .text,text + public cards_init +cards_init: + move.l #$ffff0000, d0 + move.l #16, d1 + move.l #$2, d2 + jsr syscall_vmem_map_free_to + move.l a0, (io_space_start) + rts + +; Finds the first card with the type in d0.b, and returns it's IO base address in a0, or 0 if not found +; Clobbers d1 + public find_first_card +find_first_card: + move.l io_space_start, a0 ; a0 holds the address of the current card +ffc_loop: + lea ($100,a0), a0 ; Move to the next card + move.w ($fe,a0), d1 ; Load the type of the card into d1 + beq.b ffc_done ; If the type is 0 (empty slot), we have scanned all cards, so exit the loop + cmp.b d0, d1 ; If the card is the type we want, return with the address in a0 + beq.b ffc_done + bra.b ffc_loop ; Loop back and check the next card +ffc_done: + rts + +get_all_cards: +; Gets the indexes of the cards with the specified type +; a0 is a pointer to the buffer to store the results in +; d0 is the length of the buffer in 4 byte units +; d1 is the type of card to find + move.l io_space_start, a1 ; a0 holds the address of the current card +gac_loop: + lea ($100,a1), a1 ; Move to the next card + move.w ($fe,a1), d2 ; Load the type of the card into d1 + cmp.b d1, d2 ; Check whether the type of the current card is the type we want + bne.b gac_next ; Skip the card if it is not + move.l a1, (a0) ; Put the card base into the buffer + lea ($4,a0), a0 ; Move to the next buffer location + subq.w #1, d0 ; Decement the count of available buffer locations +gac_next: + cmpa.l #$ffff00, a1 ; Check if we have gone through all the cards + beq.b gac_done ; If so, return + cmpi.b #0, d0 ; Check if we have filled the buffer + beq.b gac_done ; If so, returm + bra.b gac_loop +gac_done: + rts + + section .bss,bss +io_space_start: ds.l 1 diff --git a/cards.i b/cards.i new file mode 100644 index 0000000..665d645 --- /dev/null +++ b/cards.i @@ -0,0 +1,7 @@ + ifnd CARDS_I +CARDS_I equ 1 + xref cards_init +; Finds the first card with the type in d0.b, and returns it's IO base address in a0, or 0 if not found +; Clobbers d1 + xref find_first_card + endif diff --git a/init.68k b/init.68k new file mode 100644 index 0000000..183e8c5 --- /dev/null +++ b/init.68k @@ -0,0 +1,29 @@ + include cards.i + include initrd.i + include syscalls.i + section .text,text + public _start +_start: + move.l #tmp_stack_top, a7 + ; set up a permanent stack + move.l #2, d0 + move.l #$2, d1 + jsr syscall_vmem_map_free + adda.l #(2*4096), a0 + move.l a0, a7 + move.l #msg, a0 + jsr syscall_println + jsr cards_init + jsr initrd_init + move.l #init_name, a0 + jsr initrd_find_file +dbg: + jsr syscall_exit + + section .data,data +msg: dc.b "Hello from init",0 +init_name: dc.b "init.elf",0 + + section .bss,bss +tmp_stack: ds.b 32 +tmp_stack_top: diff --git a/initrd.68k b/initrd.68k new file mode 100644 index 0000000..526f60a --- /dev/null +++ b/initrd.68k @@ -0,0 +1,155 @@ +STORAGE_SEC equ $0 +STORAGE_CNT equ $4 +STORAGE_CMD equ $8 +STORAGE_DMADR equ $C + + include cards.i + include memory.i + include string.i + section .text,text +; Initialize the initrd reader + public initrd_init +initrd_init: + move.w #$4, d0 ; Get the pointer to the MMU card + jsr find_first_card + move.l a0, storage_card_base + rts + +; Get the start byte for a specific file in the initrd +; Pointer to name in a0 +; Number returned in d0, or 0 if not found + public initrd_find_file +initrd_find_file: + movem.l d2/a2, -(a7) + move.l a0, a2 + move.l #512, d0 + jsr malloc + move.l a0, a1 + move.l #1, d0 +iff_loop: + movem.l d0/a0/a1, -(a7) + move.l storage_card_base, a0 + move.l #1, d1 + bsr.b read_sectors + movem.l (a7)+, d0/a0/a1 + move.l (a1), d2 + bne.b .1 + move.l #0, d0 + bra.b iff_done +.1: + ; File name at (12, a1) + ; Passed in name at a2 + movem.l d0/a0/a1, -(a7) + move.l a2, a0 + adda.l #12, a1 + jsr strcmp + movem.l (a7)+, d0/a0/a1 + bne.b .2 + addi.l #1, d0 + movem.l (a7)+, d2/a2 + lsl.l #8, d0 + lsl.l #1, d0 + rts +.2: + addi.l #1, d0 + move.l (4,a1), d2 + add.l d2, d0 + bra.b iff_loop +iff_done: + movem.l (a7)+, d2/a2 + rts + +; Reads bytes of a file from the initrd +; Start byte of file in d0 +; Offset in d1 +; Length in d2 +; Buffer in a0 + public initrd_read_bytes +initrd_read_bytes: + add.l d1, d0 + move.l d2, d1 + move.l a0, a1 + move.l storage_card_base, a0 + bra.b read_bytes + +; Reads sectors from a storage card +; Card base in a0 +; Destination in a1 +; Start sector in d0.l +; Sector count in d1.l +read_sectors: + cmpi.l #0, d1 + beq.b read_sectors_done + move.l d0, (STORAGE_SEC,a0) ; Set the sector number + move.l d1, (STORAGE_CNT,a0) ; Set the sector count + move.l a1, (STORAGE_DMADR,a0) ; Set the destination address + move.w #$1, (STORAGE_CMD,a0) ; Issue a DMA read command +read_sectors_done: + rts + +; Reads bytes off a storage card +; Card base in a0 +; Destination in a1 +; Start byte in d0.l +; Byte count in d1.l +read_bytes: + movem.l d2-d5/a2/a3,-(a7) ; Save callee preserved registers + move.l d0, d4 ; Save start byte in d4 + move.l d1, d5 ; Save byte count in d5 + move.l a1, a3 ; Save destination in a6 + lsr.l #8, d0 ; Divide start byte by 512 to compute starting sector + lsr.l #1, d0 + move.l d0, d3 ; Save the starting sector in d3 + move.l #1, d1 ; Read the starting sector into the sector buffer + move.l #sec_buf, a1 + bsr.b read_sectors + move.l a3, a2 ; Load the destination into a2 + move.l d4, d0 ; Load the start byte into d0 + andi.l #$1FF, d0 ; Modulus start byte by 512 to compute sector data offset + adda.l d0, a1 ; Add the offset to the start of the sector buffer + move.l #$200, d1 ; Compute the number of bytes to transfer by subtracting the offset from 512 + sub.l d0, d1 + cmp d5, d1 ; Compare the number of bytes to transfer with the byte count + ble.b count_ok ; If it was less than the byte count, do not adjust the bytes to transfer + move.l d5, d1 ; Otherwise, cap the transfer count to the total byte count +count_ok: + move.l d1, d4 ; Save the number of bytes in d4 + subi.l #1, d1 ; Subtract 1 from the number of bytes to account for the extra loop done by dbra +start_sec_loop: ; Transfer the required bytes from the start sector to the destination buffer + move.b (a1)+, (a2)+ + dbra d1, start_sec_loop + move.l d3, d0 ; Load the starting sector into d0 + addi #1, d0 ; Compute the start of the middle sectors by adding 1 to the starting sector + move.l d4, d2 ; Load the number of bytes transferred into d2 + move.l d5, d1 ; Load the byte count into d1 + sub.l d2, d1 ; Compute the number of remaining bytes by subtracting the number of transferred bytes from the byte count + cmpi.l #0, d1 ; If there are no more bytes to read, end early + beq.b read_bytes_done + move.l d1, d4 ; Save the number of remaining bytes in d4 + lsr.l #8, d1 ; Divide remaining bytes by 512 to compute the number of middle sectors + lsr.l #1, d1 + move.l a2, a1 ; Transfer the sector data to the end of the start sector bytes + bsr.b read_sectors ; Read the middle sectors + move.l d1, d3 ; Save the number of middle sectors in d3 + lsl.l #8, d1 ; Multiply the number of middle sectors by 512 to compute the number of bytes transferred + lsl.l #1, d1 + sub.l d1, d4 ; Subtract the number of transferred bytes from the number of remaining bytes + cmpi.l #0, d4 ; If there are no more bytes to read, end early + beq.b read_bytes_done + adda.l d1, a2 ; Add the number of bytes transferred to a2 + add.l d3, d0 ; Compute the end sector number by adding the start and count of the middle sectors + move.l #1, d1 ; Set the number of sectors to read to 1 + move.l #sec_buf, a1 ; Set the read address of the sector to the sector buffer + bsr.w read_sectors ; Read the end sector + move.l d4, d1 ; Load the number of remaining bytes into d1 +end_sec_loop: ; Transfer the required bytes from the start sector to the destination buffer + move.b (a1)+, (a2)+ + dbra d1, end_sec_loop +read_bytes_done: + movem.l (a7)+, d2-d5/a2/a3 ; Restore callee preserved registers + rts + + + section .bss,bss +storage_card_base: ds.b 4 +sec_buf: ds.b 512 diff --git a/initrd.i b/initrd.i new file mode 100644 index 0000000..b9379db --- /dev/null +++ b/initrd.i @@ -0,0 +1,17 @@ + ifnd INITRD_I +INITRD_I equ 1 +; Initialize the initrd reader + xref initrd_init + +; Get the start byte for a specific file in the initrd +; 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