From 231fed08f23881e647312896943294d413400031 Mon Sep 17 00:00:00 2001 From: cuz Date: Wed, 24 Apr 2002 18:47:11 +0000 Subject: [PATCH] mod_ctrl struct cleanup git-svn-id: svn://svn.cc65.org/cc65/trunk@1260 b7a2c559-68d2-44c3-8de9-860c34a00d81 --- libsrc/common/modload.s | 108 ++++++++++++++-------------------------- 1 file changed, 38 insertions(+), 70 deletions(-) diff --git a/libsrc/common/modload.s b/libsrc/common/modload.s index f90eac4cf..955e596b3 100644 --- a/libsrc/common/modload.s +++ b/libsrc/common/modload.s @@ -68,14 +68,12 @@ Header: .res O65_HDR_SIZE ; The o65 header ; Input InputByte = Header ; Byte read from input -; Stuff needed for relocation. Since the ld65 linker uses a relocation base -; address of zero for all segments, the relocation values needed are actually -; the start addresses of the segments. Among other things this means that the -; relocation value for the text segment is the same as the start address as -; the whole module block. -TextReloc = Module ; Relocation value for code seg -DataReloc = Header + 1 ; Relocation value for data seg -BssReloc = Header + 3 ; Relocation value for bss seg +; Segment addresses. Since the ld65 linker uses a relocation base address +; of zero for all segments, the addresses of the segments are also the +; relocation values. +CodeAddr = Module ; Address of code seg +DataAddr = Header + 1 ; Address of data seg +BssAddr = Header + 3 ; Address of bss seg .data Read: jmp $FFFF ; Jump to read routine @@ -97,18 +95,6 @@ PushCtrl: 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 (the latter will be zero on return). @@ -129,20 +115,20 @@ RestoreRegBank: GetReloc: cmp #O65_SEGID_TEXT bne @L1 - lda TextReloc - ldx TextReloc+1 + lda CodeAddr + ldx CodeAddr+1 rts @L1: cmp #O65_SEGID_DATA bne @L2 - lda DataReloc - ldx DataReloc+1 + lda DataAddr + ldx DataAddr+1 rts @L2: cmp #O65_SEGID_BSS bne @L3 - lda BssReloc - ldx BssReloc+1 + lda BssAddr + ldx BssAddr+1 rts @L3: cmp #O65_SEGID_ZP @@ -344,10 +330,12 @@ _mod_load: ; Get the read function pointer from the control structure and place it into ; our call vector - ldy #MODCTRL_READ+1 - jsr LoadCtrl + ldy #MODCTRL_READ + lda (Ctrl),y sta Read+1 - stx Read+2 + iny + lda (Ctrl),y + sta Read+2 ; Read the o65 header: C->read (C, &H, sizeof (H)) @@ -418,58 +406,33 @@ OptDone: 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. +; We got the memory block. Place a pointer to the memory block also in the +; module control structure. GotMem: lda Module ; Ctrl->module = Module; ldy #MODCTRL_MODULE sta (Ctrl),y - ldy #MODCTRL_CODE ; Ctrl->code = Module; - 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. -; Since the linker relocates all segments to zero, these addresses are also -; the relocation values for the segments. +; Calculate the start addresses of the segments. Since the linker uses a +; base address of zero for all segments, the load addresses are also the +; relocation values for the segments. - ldy #MODCTRL_DATA lda Module add Header + O65_HDR_TLEN - sta (Ctrl),y - sta DataReloc - iny + sta DataAddr lda Module + 1 adc Header + O65_HDR_TLEN + 1 - sta (Ctrl),y - sta DataReloc + 1 + sta DataAddr + 1 - ldy #MODCTRL_BSS lda Module add TPtr - sta (Ctrl),y - sta BssReloc - iny + sta BssAddr lda Module+1 add TPtr+1 - sta (Ctrl),y - sta BssReloc + 1 + sta BssAddr + 1 ; Control structure is complete now. Load code and data segment into memory. ; The sum of the sizes of code+data segment is still in TPtr. @@ -494,8 +457,8 @@ CLoop: lda Header,x beq Reloc Undef: jmp FormatError -; Number of undefined references was zero. Next sections are the relocation -; tables for code and data segment. Relocate the code segment +; Number of undefined references was zero. Next come the relocation tables +; for code and data segment. Relocate the code segment Reloc: lda Module ldx Module + 1 ; Code segment address @@ -503,14 +466,19 @@ Reloc: lda Module ; Relocate the data segment - ldy #MODCTRL_DATA + 1 - jsr LoadCtrl ; Get data segment address + lda Module + add Header + O65_HDR_TLEN + pha + lda Module + 1 + adc Header + O65_HDR_TLEN + 1 + tax + pla ; Date segment address in a/x jsr RelocSeg -; Clear the bss segment +; Clear the bss segment: memset (bss_addr, 0, bss_size) - ldy #MODCTRL_BSS + 1 - jsr LoadCtrl ; Load bss segment address + lda BssAddr + ldx BssAddr + 1 jsr pushax jsr push0 lda Header + O65_HDR_BLEN -- 2.39.5