diff options
| author | Astrid Smith | 2010-09-10 19:11:48 -0700 |
|---|---|---|
| committer | Astrid Smith | 2010-09-10 19:11:48 -0700 |
| commit | f04517792ecbb28b644063f98d138079f7ca53f6 (patch) | |
| tree | a3a0296b76756e58fd413efa16ec411e3e086f5e /opcodes.asm | |
| parent | 522b7ce4d83ef08fadc9fbc4b700a2ef6bbd9c0e (diff) | |
Lazy, slow hack to FETCHW and FETCHWI becuase I forgot about endianness
Diffstat (limited to 'opcodes.asm')
| -rw-r--r-- | opcodes.asm | 26 |
1 files changed, 12 insertions, 14 deletions
diff --git a/opcodes.asm b/opcodes.asm index 2db3351..e366b90 100644 --- a/opcodes.asm +++ b/opcodes.asm @@ -30,17 +30,14 @@ PUTB MACRO ;; Macro to read a word from main memory at register \1 ;; (unaligned). Puts the word read in \2. - ;; - ;; <debrouxl> It decrements sp by 2, but stores the result at - ;; sp, not at 1(sp). So you essentially get a "free" shift - ;; left by 8 bits. Much faster than lsl.w / rol.w #8, at - ;; least. FETCHW MACRO ; ?/16 move.w \1,d1 ; 4/2 bsr deref ; ?/4 - move.b (a0),-(sp) ; 18/4 - move.w (sp)+,\2 ; 8/2 - move.b (a0),\2 ; 14/4 + ;; XXX SPEED + move.b (a0)+,d2 + move.b (a0),\2 + rol.w #8,\2 + move.b d2,\2 ENDM ;; Macro to write a word in \1 to main memory at \2 (regs only) @@ -88,12 +85,13 @@ FETCHBI MACRO ; 8 cycles, 2 bytes ENDM ;; Macro to read an immediate word (unaligned) into \1. -FETCHWI MACRO ; 28 cycles, 6 bytes - ;; See FETCHW for an explanation of this trick. - move.b (epc)+,-(sp) ; 12/2 - move.w (sp)+,\1 ; 8/2 - move.b (epc)+,\1 ; 8/2 - ENDM ; 28/6 +FETCHWI MACRO ; 42 cycles, 8 bytes + ;; XXX SPEED + move.b (epc)+,d2 + move.b (epc)+,\1 + rol.w #8,\1 + move.b d2,\1 + ENDM ;; == Common Opcode Macros ========================================= |