From 0e4eef1f0fdb68e9841e929a6623894c97cd0937 Mon Sep 17 00:00:00 2001 From: cuz Date: Sun, 21 Apr 2002 14:29:30 +0000 Subject: [PATCH] New files for loading modules at runtime git-svn-id: svn://svn.cc65.org/cc65/trunk@1252 b7a2c559-68d2-44c3-8de9-860c34a00d81 --- libsrc/common/Makefile | 2 + libsrc/common/modfree.s | 57 +++++ libsrc/common/modload.s | 541 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 600 insertions(+) create mode 100644 libsrc/common/modfree.s create mode 100644 libsrc/common/modload.s diff --git a/libsrc/common/Makefile b/libsrc/common/Makefile index d16393381..93d51ec7a 100644 --- a/libsrc/common/Makefile +++ b/libsrc/common/Makefile @@ -88,6 +88,8 @@ S_OBJS = _fdesc.o \ memcmp.o \ memcpy.o \ memset.o \ + modfree.o \ + modload.o \ printf.o \ rand.o \ setjmp.o \ diff --git a/libsrc/common/modfree.s b/libsrc/common/modfree.s new file mode 100644 index 000000000..cc879ab08 --- /dev/null +++ b/libsrc/common/modfree.s @@ -0,0 +1,57 @@ +;*****************************************************************************/ +;* */ +;* modfree.s */ +;* */ +;* Free loaded o65 modules */ +;* */ +;* */ +;* */ +;* (C) 2002 Ullrich von Bassewitz */ +;* Wacholderweg 14 */ +;* D-70597 Stuttgart */ +;* EMail: uz@musoftware.de */ +;* */ +;* */ +;* This software is provided 'as-is', without any expressed or implied */ +;* warranty. In no event will the authors be held liable for any damages */ +;* arising from the use of this software. */ +;* */ +;* Permission is granted to anyone to use this software for any purpose, */ +;* including commercial applications, and to alter it and redistribute it */ +;* freely, subject to the following restrictions: */ +;* */ +;* 1. The origin of this software must not be misrepresented; you must not */ +;* claim that you wrote the original software. If you use this software */ +;* in a product, an acknowledgment in the product documentation would be */ +;* appreciated but is not required. */ +;* 2. Altered source versions must be plainly marked as such, and must not */ +;* be misrepresented as being the original software. */ +;* 3. This notice may not be removed or altered from any source */ +;* distribution. */ +;* */ +;*****************************************************************************/ + + + + .include "modload.inc" + + .import _free + .importzp ptr1 + +;------------------------------------------------------------------------------ +; mod_free: Free a loaded module + +.code +_mod_free: + sta ptr1 + stx ptr1+1 ; Save parameter + + ldy #MODCTRL_MODULE + 1 + lda (ptr1),y + tax + dey + lda (ptr1),y ; Load module pointer + + jmp _free ; Free the module memory + + diff --git a/libsrc/common/modload.s b/libsrc/common/modload.s new file mode 100644 index 000000000..11740793c --- /dev/null +++ b/libsrc/common/modload.s @@ -0,0 +1,541 @@ +;*****************************************************************************/ +;* */ +;* modload.s */ +;* */ +;* o65 module loader for the cc65 library */ +;* */ +;* */ +;* */ +;* (C) 2002 Ullrich von Bassewitz */ +;* Wacholderweg 14 */ +;* D-70597 Stuttgart */ +;* EMail: uz@musoftware.de */ +;* */ +;* */ +;* This software is provided 'as-is', without any expressed or implied */ +;* warranty. In no event will the authors be held liable for any damages */ +;* arising from the use of this software. */ +;* */ +;* Permission is granted to anyone to use this software for any purpose, */ +;* including commercial applications, and to alter it and redistribute it */ +;* freely, subject to the following restrictions: */ +;* */ +;* 1. The origin of this software must not be misrepresented; you must not */ +;* claim that you wrote the original software. If you use this software */ +;* in a product, an acknowledgment in the product documentation would be */ +;* appreciated but is not required. */ +;* 2. Altered source versions must be plainly marked as such, and must not */ +;* be misrepresented as being the original software. */ +;* 3. This notice may not be removed or altered from any source */ +;* distribution. */ +;* */ +;*****************************************************************************/ + + + + .include "o65.inc" + .include "modload.inc" + + .import pushax, pusha0, push0, push1, decax1 + .import _malloc, _free, _memset + .importzp sp, ptr1, tmp1, regbank + + .macpack generic + +;------------------------------------------------------------------------------ +; Variables stored in the register bank in the zero page. Placing the variables +; here will protect them when calling other C functions. + +Module = regbank+0 ; Pointer to module memory +Ctrl = regbank+2 ; Pointer to mod_ctrl structure +TPtr = regbank+4 ; Pointer to module data for relocation + +;------------------------------------------------------------------------------ +; Static module data + +.bss + +; Save areas and error recovery data +Stack: .byte 0 ; Old stackpointer +RegBankSave: .res 6 ; Save area for register bank + +; The header of the o65 file. Since we don't need the 8 bytes any longer, +; once we've checked them, we will overlay them with other data to save a +; few bytes. +Header: .res O65_HDR_SIZE ; The o65 header + +; Input +InputByte = Header ; Byte read from input + +; Stuff needed for relocation +TextReloc = Header + 1 ; Relocation value for code seg +DataReloc = Header + 3 ; Relocation value for data seg +BssReloc = Header + 5 ; Relocation value for bss seg + +.data +Read: jmp $FFFF ; Jump to read routine + +.rodata +ExpectedHdr: .byte $01, $00 ; non C64 marker + .byte $6F, $36, $35 ; Magic ("o65") + .byte $00 ; Version + .word $0000 ; Mode word +ExpectedHdrSize = * - ExpectedHdr + + +;------------------------------------------------------------------------------ +; PushCtrl: Push the address of the control structure onto the C stack. + +.code +PushCtrl: + lda Ctrl + ldx Ctrl+1 + jmp pushax + +;------------------------------------------------------------------------------ +; LoadCtrl: Load a word from the control structure into a/x. The offset of the +; high byte is passed in Y. + +.code +LoadCtrl: + lda (Ctrl),y + tax + dey + lda (Ctrl),y + rts + +;------------------------------------------------------------------------------ +; RestoreRegBank: Restore the register bank contents from the save area. Will +; destroy A and X + +.code +RestoreRegBank: + ldx #6-1 +@L1: lda RegBankSave,x + sta regbank,x + dex + bpl @L1 + rts + +;------------------------------------------------------------------------------ +; GetReloc: Return a relocation value based on the segment in A + +.code +GetReloc: + cmp #O65_SEGID_TEXT + bne @L1 + lda TextReloc + ldx TextReloc+1 + rts + +@L1: cmp #O65_SEGID_DATA + bne @L2 + lda DataReloc + ldx DataReloc+1 + rts + +@L2: cmp #O65_SEGID_BSS + bne @L3 + lda BssReloc + ldx BssReloc+1 + rts + +@L3: lda #MLOAD_ERR_FMT +; bne CleanupAndExit ; Branch always + +;------------------------------------------------------------------------------ +; CleanupAndExit: Free any allocated resources, restore the stack and return +; to the caller. + +.code +CleanupAndExit: + +; Restore the stack so we may return to the caller from here + + ldx Stack + txs + +; Save the error return code + + pha + +; Check if we have to free the allocated block + + lda Module + ora Module+1 + beq @L1 ; Jump if no memory allocated + + lda Module + ldx Module+1 + jsr _free ; Free the allocated block + +; Restore the register bank + +@L1: jsr RestoreRegBank + +; Restore the error code and return to the caller + + ldx #$00 ; Load the high byte + pla + rts + +;------------------------------------------------------------------------------ +; ReadByte: Read one byte with error checking into InputByte and A. + +.code +ReadByte: + +; C->read (C, &B, 1) + + jsr PushCtrl + lda #InputByte + jsr pushax + jsr push1 + jsr Read + +; Check the return code and bail out in case of problems + + tax + beq @L1 ; Jump if ok + lda #MLOAD_ERR_READ + bne CleanupAndExit + +; Done + +@L1: lda InputByte +Done: rts + +;------------------------------------------------------------------------------ +; RelocSeg: Relocate the segment pointed to by a/x + +.code +RelocSeg: + jsr decax1 ; Start value is segment-1 + sta TPtr + stx TPtr+1 + +Loop: jsr ReadByte ; Read byte from relocation table + beq Done ; Bail out if end of table reached + + cmp #255 ; Special offset? + bne @L1 + +; Increment offset by 254 and continue + + lda TPtr + add #254 + sta TPtr + bcc Loop + inc TPtr+1 + jmp Loop + +; Increment offset by A + +@L1: add TPtr + sta TPtr + bcc @L2 + inc TPtr+1 + +; Read the relocation byte, extract the segment id, fetch the corresponding +; relocation value and place it into ptr1 + +@L2: jsr ReadByte + and #O65_SEGID_MASK + jsr GetReloc + sta ptr1 + stx ptr1+1 + +; Get the relocation byte again, this time extract the relocation type. + + lda InputByte + and #O65_RTYPE_MASK + +; Check for and handle the different relocation types. + + cmp #O65_RTYPE_WORD + bne @L3 + ldy #0 + clc + lda (TPtr),y + adc ptr1 + sta (TPtr),y + iny + bne @L4 ; Branch always (add high byte) + +@L3: cmp #O65_RTYPE_HIGH + bne @L5 + jsr ReadByte ; Read low byte from relocation table + ldy #0 + clc + adc ptr1 ; We just need the carry +@L4: lda (TPtr),y + adc ptr1+1 + sta (TPtr),y + jmp Loop ; Done, next entry + +@L5: cmp #O65_RTYPE_LOW + beq @L6 + +; Problem: Invalid relocation code + + lda #MLOAD_ERR_FMT + jmp CleanupAndExit + +@L6: ldy #0 + clc + lda (TPtr),y + adc ptr1 + sta (TPtr),y + +; Finished with this relocation + + jmp Loop + +;------------------------------------------------------------------------------ +; mod_load: Load and relocate an o65 module + +.code +_mod_load: + +; Save the register bank and clear the Module pointer + + pha + ldy #6 +@L1: lda regbank-1,y + sta RegBankSave-1,y + dey + bne @L1 + sty Module + sty Module+1 + pla + +; Save the passed parameter + + sta Ctrl + stx Ctrl+1 + +; Save the stack pointer so we can bail out even from subroutines + + tsx + stx Stack + +; Get the read function pointer from the control structure and place it into +; our call vector + + ldy #MODCTRL_READ+1 + jsr LoadCtrl + sta Read+1 + stx Read+2 + +; Read the o65 header: C->read (C, &H, sizeof (H)) + + jsr PushCtrl + lda #
Header + jsr pushax + lda #O65_HDR_SIZE + jsr pusha0 ; Always less than 256 + jsr Read + +; Check the return code + + tax + beq @L2 + lda #MLOAD_ERR_READ + jmp CleanupAndExit + +; We read the o65 header successfully. Validate it. + +@L2: ldy #ExpectedHdrSize-1 +@L3: lda Header,y + cmp ExpectedHdr,y + beq @L4 + lda #MLOAD_ERR_HDR + jmp CleanupAndExit +@L4: dey + bpl @L3 + +; Header is ok as far as we can say now. Read and skip all options. We may +; add a check here for the OS option later. + +Opt: jsr ReadByte + beq OptDone ; Jump if done + sta TPtr ; Use TPtr as a counter +OneOpt: dec TPtr + beq Opt ; Next option + jsr ReadByte ; Skip one byte + jmp OneOpt +OptDone: + +; Skipped all options. Calculate the sizes of several areas needed later + + lda Header + O65_HDR_TLEN + add Header + O65_HDR_DLEN + sta TPtr + lda Header + O65_HDR_TLEN + 1 + adc Header + O65_HDR_DLEN + 1 + sta TPtr+1 + lda TPtr + add Header + O65_HDR_BLEN + sta tmp1 + lda TPtr+1 + adc Header + O65_HDR_BLEN + 1 + +; Load the total module size into a/x and store it into the control structure + + ldy #MODCTRL_MODULE_SIZE + 1 + sta (Ctrl),y + tax + dey + lda tmp1 + sta (Ctrl),y + +; Allocate memory, check if we got it + + jsr _malloc + sta Module + stx Module+1 + ora Module+1 + bne GotMem + +; Could not allocate memory + + lda #MLOAD_ERR_MEM + jmp CleanupAndExit + +; We got the memory block. Setup the pointers and sizes in the control +; structure. We will use internal knowlege about the layout of the structure +; here to save some code. + +GotMem: lda Module + ldy #MODCTRL_MODULE + sta (Ctrl),y + ldy #MODCTRL_CODE + sta (Ctrl),y + txa + iny + sta (Ctrl),y ; MODCTRL_CODE+1 + ldy #MODCTRL_MODULE+1 + sta (Ctrl),y + +; The following loop will also copy some information that is not needed just +; to save some code. + + ldx #O65_HDR_TLEN + ldy #MODCTRL_CODE_SIZE +CLoop: lda Header,x + sta (Ctrl),y + inx + iny + cpy #MODCTRL_SIZE + bne CLoop + +; Missing in the control structure now: start of the data and bss segments + + ldy #MODCTRL_DATA + lda Module + add Header + O65_HDR_TLEN + sta (Ctrl),y + iny + lda Module + 1 + adc Header + O65_HDR_TLEN + 1 + sta (Ctrl),y + + ldy #MODCTRL_BSS + lda Module + add TPtr + sta (Ctrl),y + iny + lda Module+1 + add TPtr+1 + sta (Ctrl),y + +; Control structure is complete now. Load code and data segment into memory. +; The sum of the sizes of code and data segment is still in TPtr. +; C->read (C, C->module, H.tlen + H.dlen) + + jsr PushCtrl + lda Module + ldx Module+1 + jsr pushax + lda TPtr + ldx TPtr+1 + jsr pushax + jsr Read + +; Check for errors + + tax + beq LoadOk + lda #MLOAD_ERR_READ + jmp CleanupAndExit + +; We've got the code and data segments in memory. Next section contains +; undefined references which we don't support. So check if the count of +; undefined references is actually zero. + +LoadOk: jsr ReadByte + bne Undef + jsr ReadByte + beq Reloc +Undef: lda #MLOAD_ERR_FMT + jmp CleanupAndExit + +; Number of undefined references was zero. Next sections are the relocation +; tables for code and data segment. Before doing the actual relocation, we +; have to setup the relocation values for the three segments. + +Reloc: lda Module + sub Header + O65_HDR_TBASE + sta TextReloc + lda Module + 1 + sbc Header + O65_HDR_TBASE + 1 + sta TextReloc + 1 + + ldy #MODCTRL_DATA + lda (Ctrl),y + sub Header + O65_HDR_DBASE + sta DataReloc + iny + lda (Ctrl),y + sbc Header + O65_HDR_DBASE + 1 + sta DataReloc + 1 + + ldy #MODCTRL_BSS + lda (Ctrl),y + sub Header + O65_HDR_BBASE + sta BssReloc + iny + lda (Ctrl),y + sbc Header + O65_HDR_BBASE + 1 + sta BssReloc + 1 + +; Relocate the code segment + + lda Module + ldx Module + 1 ; Code segment address + jsr RelocSeg + +; Relocate the data segment + + ldy #MODCTRL_DATA + 1 + jsr LoadCtrl ; Get data segment address + jsr RelocSeg + +; Clear the bss segment + + ldy #MODCTRL_BSS + 1 + jsr LoadCtrl ; Load bss segment address + jsr pushax + jsr push0 + ldy #MODCTRL_BSS_SIZE + 1 + jsr LoadCtrl ; Load bss segment size + jsr _memset ; memset (bss, 0, bss_size); + +; We're done. Restore the register bank and return a success code + + jsr RestoreRegBank + lda #MLOAD_OK + rts + -- 2.39.5