diff options
Diffstat (limited to 'main.asm')
| -rw-r--r-- | main.asm | 45 |
1 files changed, 22 insertions, 23 deletions
@@ -44,52 +44,54 @@ ;; Macro to read a byte from main memory at register \1. Puts ;; the byte read in \2. FETCHB MACRO ; 14 cycles, 4 bytes - move.b (\1.w,a6),\2 + move.b 0(a6,\1.w),\2 ENDM ;; Macro to write a byte in \1 to main memory at \2 (regs only) PUTB MACRO ; 14 cycles, 4 bytes - move.b \1,(\2,a6) + move.b \1,(a6,\2) ENDM ;; Macro to read a word from main memory at register \1 ;; (unaligned). Puts the word read in \2. FETCHW MACRO ; 32 cycles, 10 bytes - move.b 1(\1.w,a6),\2 ; 14/4 + move.b 1(a6,\1.w),\2 ; 14/4 ror.w #8,\2 ; 4/2 - move.b (\1.w,a6),\2 ; 14/4 + move.b (a6,\1.w),\2 ; 14/4 ENDM ;; Macro to write a word in \1 to main memory at \2 (regs only) ;; XXX ALIGNMENT PUTW MACRO ; 14 cycles, 4 bytes - move.b \1,(\2,a6) + move.b \1,(a6,\2) ENDM ;; == Immediate Memory Macros == - ;; Macro to read an immediate byte into \2. + ;; Macro to read an immediate byte into \1. FETCHBI MACRO ; 18 cycles, 6 bytes addq.w #1,d2 ; 4/2 - move.b -1(d2.w,a6),\2 ; 14/4 + move.b -1(a6,d2.w),\1 ; 14/4 ENDM - ;; Macro to read an immediate word (unaligned) into \2. + ;; Macro to read an immediate word (unaligned) into \1. FETCHWI MACRO ; 36 cycles, 12 bytes addq.w #2,d2 ; 4/2 - move.b -1(d2.w,a6),\2 ; 14/4 + move.b -1(a6,d2.w),\1 ; 14/4 rol.w #8,d2 ; 4/2 - move.b -2(d2.w,a6),\2 ; 14/4 + move.b -2(a6,d2.w),\1 ; 14/4 ENDM ;; == Common Opcode Macros ========================================= ;; Forces alignment _align SET 0 + START MACRO ORG emu_plain_op+_align _align SET _align+32 ENDM + ;; When you want to use the high reg of a pair, use this first LOHI MACRO ; 6 cycles, 2 bytes ror #8,\1 @@ -100,10 +102,10 @@ HILO MACRO ; 6 cycles, 2 bytes rol #8,\1 ENDM -DONE MACRO ; 8 cycles, 2 bytes ;; calc84maniac suggests putting emu_fetch into this in order ;; to save 8 cycles per instruction, at the expense of code ;; size +DONE MACRO ; 8 cycles, 2 bytes jmp (a2) ENDM @@ -148,9 +150,7 @@ _main: rts emu_setup: - eor.l a5,a5 - eor.l a4,a4 - movea emu_instr_table,a3 + movea emu_plain_op,a3 movea emu_fetch(pc),a2 ;; XXX finish @@ -177,7 +177,7 @@ emu_fetch: eor.w d0,d0 ; 4 cycles move.b (a4)+,d0 ; 8 cycles rol.w #5,d0 ; 4 cycles adjust to actual alignment - jmp (a3,d0) ;14 cycles + jmp 0(a3,d0) ;14 cycles ;; overhead: 30 cycles storage: @@ -269,7 +269,7 @@ emu_op_07: ;; Rotate A left, carry bit gets top bit ;; Flags: H,N=0; C aff. START - rol.b d3,1 + rol.b #1,d3 DONE emu_op_08: @@ -292,8 +292,7 @@ emu_op_0a: ;; A <- (BC) ;; No flags START - FETCHB d4 - move.b d1,d3 + FETCHB d4,d3 DONE emu_op_0b: @@ -332,7 +331,7 @@ emu_op_0f: ;; Rotate A right, carry bit gets top bit ;; Flags: H,N=0; C aff. START - ror.b d3,1 + ror.b #1,d3 DONE emu_op_10: @@ -403,7 +402,7 @@ emu_op_17: ;; RLA ;; Flags: P,N=0; C aff. START - roxl.b 1,d3 + roxl.b #1,d3 DONE emu_op_18: @@ -463,7 +462,7 @@ emu_op_1f: ;; RRA ;; Flags: H,N=0; C aff. START - roxr.b d3 + roxr.b #1,d3 DONE emu_op_20: @@ -639,7 +638,7 @@ emu_op_34: ;; Increment byte ;; SPEED can be made faster START - FETCHB d6 + FETCHB d6,d1 addq.b #1,d1 PUTB d1,d6 DONE @@ -649,7 +648,7 @@ emu_op_35: ;; Decrement byte ;; SPEED can be made faster START - FETCHB d6 + FETCHB d6,d1 subq.b #1,d1 PUTB d1,d6 DONE |