diff options
Diffstat (limited to 'f65')
| -rw-r--r-- | f65/Makefile | 10 | ||||
| -rw-r--r-- | f65/README | 32 | ||||
| -rwxr-xr-x | f65/asm2fake65.pl | 72 | ||||
| -rw-r--r-- | f65/f65.c | 68 | ||||
| -rw-r--r-- | f65/f65.h | 129 |
5 files changed, 0 insertions, 311 deletions
diff --git a/f65/Makefile b/f65/Makefile deleted file mode 100644 index 91adf06..0000000 --- a/f65/Makefile +++ /dev/null @@ -1,10 +0,0 @@ -CFLAGS=-Wall - -all: test - -f65.o: f65.c f65.h - -f65test: f65.o f65test.c - -test: f65test - ./f65test diff --git a/f65/README b/f65/README deleted file mode 100644 index 0f7d0a3..0000000 --- a/f65/README +++ /dev/null @@ -1,32 +0,0 @@ -f65 - "fake 6502" porting layer - -This is a set of C macros that implements most of the 6502 assembly -language instructions, plus a perl script to convert 6502 assembly -source to C code that calls the macros. You can use it to assist in -porting 6502 assembly routines to C, using either the original asm -source, or a disassembly created with da65. - -What's implemented: 64K of memory. The A/X/Y/S registers. The carry, -zero, and negative flags. Most arithmetic and logic instructions. The -stack. Conditional branches and absolute jumps are implemented as C -goto's. JSR is implemented as a real C function call, and RTS is a -real C return. Labels in the assembly source become C labels (aka goto -targets). Equates in the asm source become C variables. - -What's not implemented: The D flag, and decimal mode in general. The -V flag, and branches based on it. The I and B flags. Interrupts -and the RTI instruction. The Program Counter (though branches, JMP, -JSR, and RTS are implemented without it). ROM routines (including -I/O). Indirect JMP. The "CPU bug" that causes e.g. 'LDA ($FF),y' to -take its high byte from $00 rather than $100. (zeropage, x) addressing -mode. - -I wrote this specifically to port the decompression algorithm from -UnAlf 1.4. Instructions not used by UnAlf probably aren't implemented, -or if they are, they're untested. - -The perl script doesn't magically convert a whole 6502 program to C -source. You'll have to figure out which parts of the 6502 program are -subroutines, and put them in their own C functions. Any data (.byte, -.word, etc) won't be in the C program. Anything that does I/O must be -rewritten in C. diff --git a/f65/asm2fake65.pl b/f65/asm2fake65.pl deleted file mode 100755 index 78031a7..0000000 --- a/f65/asm2fake65.pl +++ /dev/null @@ -1,72 +0,0 @@ -#!/usr/bin/perl -w - -LINE: while(<>) { - chomp; - - next if /^\s*$/; - next if /^\s+\.byte/; - next if /^\s+\.setcpu/; - next if /^\s+;/; - - # join lone label: with next line - if(/^[a-zA-Z0-9_]+:\s*$/) { - $_ .= <>; - redo LINE; - } - - # comment-only lines: - if(/^;\s+(.*)/) { - print "/* $1 */\n"; - next; - } - - if(s/(^[a-zA-Z0-9_]+):?//) { - my $label = $1; - if(/:=\s*\$([0-9A-F]{4})/) { - print "u16 $label = 0x$1;\n"; - next; - } elsif(/\.byte/) { - /; ([0-9A-F]{4})\s/; - print "u16 $label = 0x$1;\n"; - next; - } else { - print "$label:\n"; - } - } - - s/\s+;.*//; - s/^\s*([a-z]{3})\s*//; - my $mnem = $1; - s/\s*$//; - my $operand = $_; - my $arg = ""; - - print "\t"; - - if(!$operand) { - $mnem .= "_a" if $mnem =~ /asl|lsr|rol|ror/; - print $mnem . "();\n"; - next; - } - - $operand =~ s,\$,0x,; - $operand =~ s,;.*,,; - - #print "mnem '$mnem', operand '$operand'\n"; - if($operand =~ /#(.*)/) { - print $mnem . "_i(" . $1 . ");\n"; - next; - } - - if($operand =~ /\(([^)]+)\),y/) { - print $mnem . "_ind_y(" . $1 . ");\n"; - next; - } - - if($operand =~ /(.+),([xy])/) { - print $mnem . "_abs_" . $2 . "(" . $1 . ");\n"; - next; - } - - print $mnem . "(" . $operand . ");\n"; -} diff --git a/f65/f65.c b/f65/f65.c deleted file mode 100644 index 952eac3..0000000 --- a/f65/f65.c +++ /dev/null @@ -1,68 +0,0 @@ -/* fake 6502. a perl script converts this: - - ldy #10 -loop: - lda blah,y - sta (p1),y - dey - bpl loop - -to something like: - ldy_i(10) -loop: - lda_absy(blah) - sta_zpy(p1) - dey(); - bpl(loop); - -where e.g. - - #define ldy_i(x) Y=x; ZF=!Y; NF=Y&0x80; - - #define lda_absy(x) A=mem[x+y]; ZF=!A; NF=A&0x80; - - #define sta_zpy(x) mem[(mem[x] | mem[x+1] << 8) + y] = A; - - #define dey() Y--; ZF=!Y; NF=Y&0x80; - - #define bpl(x) if(!NF) goto x - -...and the 'loop:' is a real C line label. - -we don't worry about the V flag since unalf doesn't use it. - -This isn't emulation exactly, and it isn't dynamic recompilation because -it's static. "Static recompilation" maybe? - -*/ - -#include "f65.h" - -u8 A, X, Y, S = 0xff, tmp; /* tmp is result for cmp/cpx/cpy */ -u8 mem[1 << 16]; /* 64K */ -u8 *stack = mem + 0x100; /* page 1 */ - -u8 CF, ZF, NF; /* flags should really be a bitfield, *shrug* */ - -unsigned int wtmp; - -void dump_state(void) { - fprintf(stderr, - "A = $%02x X = $%02x Y = $%02x S = $%02x | " - "CF = %d ZF=%d NF=%d\n", - A, X, Y, S, (CF ? 1 : 0), (ZF ? 1 : 0), (NF ? 1 : 0)); -} - -void dump_mem(int start, int end) { - int count = 0; - while(start <= end) { - if(count % 16 == 0) { - if(count) fputc('\n', stderr); - fprintf(stderr, "%04x:", start); - } - fprintf(stderr, " %02x", mem[start]); - count++; - start++; - } - fputc('\n', stderr); -} diff --git a/f65/f65.h b/f65/f65.h deleted file mode 100644 index 2d5a66a..0000000 --- a/f65/f65.h +++ /dev/null @@ -1,129 +0,0 @@ -#include <stdio.h> - -#define u8 unsigned char -#define u16 unsigned short - -extern u8 A, X, Y, S, tmp; /* tmp is result for cmp/cpx/cpy */ -extern u8 mem[1 << 16]; /* 64K */ -extern u8 *stack; /* page 1 */ - -extern unsigned int wtmp; /* wide temporary for adc/sbc */ - -extern u8 CF, ZF, NF; /* flags should really be a bitfield, *shrug* */ - -extern void dump_state(void); -extern void dump_mem(int start, int end); - -#define dump_zp() dump_mem(0, 0xff); -#define dump_stack() dump_mem(0x100, 0x1ff); -#define dump_page(x) dump_mem(x * 0x100, x * 0x100 + 0x1ff); - -#define _ind_y(x) mem[Y + (mem[x] | (mem[x+1] << 8))] - -#define setnz(x) ZF=!x; NF=(x&0x80)!=0; - -#define pha() stack[S--] = A; -#define pla() A = stack[++S]; setnz(A); -#define php() stack[S--] = (NF<<7 | ZF<<1 | CF); -#define plp() tmp = stack[++S]; NF=(tmp&0x80)!=0 ; ZF=(tmp&0x02)!=0; CF=tmp&0x01; - -#define lda_i(x) A=x; setnz(A); -#define ldy_i(x) Y=x; setnz(Y); -#define ldx_i(x) X=x; setnz(X); -#define lda(x) A=mem[x]; setnz(A); -#define ldx(x) X=mem[x]; setnz(X); -#define ldy(x) Y=mem[x]; setnz(Y); -#define lda_abs_x(x) A=mem[x+X]; setnz(A); -#define lda_abs_y(x) A=mem[x+Y]; setnz(A); -#define lda_ind_y(x) A=_ind_y(x); setnz(A); - -#define sta(x) mem[x] = A; -#define sta_abs_x(x) mem[x + X] = A; -#define sta_abs_y(x) mem[x + Y] = A; -#define sta_ind_y(x) _ind_y(x) = A; - -#define stx(x) mem[x] = X; -#define sty(x) mem[x] = Y; - -#define sec() CF=1; -#define clc() CF=0; - -#define tax() X=A; setnz(X); -#define tay() Y=A; setnz(Y); -#define txa() A=X; setnz(A); -#define tya() A=Y; setnz(A); -#define txs() S=X; setnz(S); -/* note: tsx doesn't affect flags */ -#define tsx() X=S; - -#define _ror(x) tmp=x&1; x>>=1; x|=(CF<<7); CF=tmp; setnz(x); -#define _rol(x) tmp=(x&0x80)!=0; x<<=1; x|=CF; CF=tmp; setnz(x); - -#define ror_a() _ror(A); -#define rol_a() _rol(A); -#define ror(x) _ror(mem[x]); -#define rol(x) _rol(mem[x]); - -#define _lsr(x) CF=x&1; x>>=1; setnz(x); -#define _asl(x) CF=(x&0x80)!=0; x<<=1; setnz(x); - -#define lsr_a() _lsr(A); -#define asl_a() _asl(A); -#define lsr(x) _lsr(mem[x]); -#define asl(x) _asl(mem[x]); - -#define inx() X++; setnz(X); -#define iny() Y++; setnz(Y); -#define dex() X--; setnz(X); -#define dey() Y--; setnz(Y); - -#define inc(x) mem[x]++; setnz(mem[x]); -#define dec(x) mem[x]--; setnz(mem[x]); - -#define jsr(x) x(); -#define rts() return; - -#define jmp(x) goto x; -#define bne(x) if(!ZF) goto x; -#define beq(x) if(ZF) goto x; -#define bcc(x) if(!CF) goto x; -#define bcs(x) if(CF) goto x; -#define bpl(x) if(!NF) goto x; -#define bmi(x) if(NF) goto x; - -#define ora_i(x) A|=x; setnz(A); -#define ora(x) A|=mem[x]; setnz(A); - -#define and_i(x) A&=x; setnz(A); -#define and(x) A&=mem[x]; setnz(A); -#define and_abx_x(x) A&=mem[x+X]; setnz(A); -#define and_abs_y(x) A&=mem[x+Y]; setnz(A); -#define and_ind_y(x) A&=_ind_y(x); setnz(A); - -#define eor_i(x) A^=x; setnz(A); -#define eor(x) A^=mem[x]; setnz(A); - -#define adc_i(x) wtmp=A+x+CF; A=wtmp&0xff; CF=(wtmp&0x100)!=0; setnz(A); -#define adc(x) adc_i(mem[x]); -#define adc_abs_x(x) adc_i(mem[x+X]); -#define adc_abs_y(x) adc_i(mem[x+Y]); -#define adc_ind_y(x) adc_i(_ind_y(x)); - -/* TODO: actually check this logic! */ -#define _sub(dst,orig,c,operand) wtmp=orig+(operand^0xff)+c; dst=wtmp&0xff; CF=(wtmp&0x100)!=0; setnz(dst); - -#define sbc_i(x) _sub(A,A,CF,x) -#define sbc(x) _sub(A,A,CF,mem[x]) -#define cmp_i(x) _sub(tmp,A,1,x) -#define cpy_i(x) _sub(tmp,Y,1,x) -#define cpx_i(x) _sub(tmp,X,1,x) -#define cmp(x) cmp_i(mem[x]) -#define cmp_abs_x(x) cmp_i(mem[x+X]) -#define cpy(x) cpy_i(mem[x]) -#define cpx(x) cpx_i(mem[x]) - -#define nop() {} - -/* this should produce a compile error instead */ -// #define brk() nop() - |