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Added proper 65sc02, 65ce02 and 4510 detection.

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This commit is contained in:
Marco van den Heuvel 2018-02-26 19:19:13 -08:00
parent b0ef67d14c
commit 122def9f12
2 changed files with 30 additions and 6 deletions
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2
include/6502.h
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@ -51,6 +51,8 @@ typedef unsigned size_t;
#define CPU_65C02 1
#define CPU_65816 2
#define CPU_4510 3
#define CPU_65SC02 4
#define CPU_65CE02 5
unsigned char getcpu (void);
/* Detect the CPU the program is running on */

34
libsrc/common/getcpu.s
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@ -10,9 +10,11 @@
; Subroutine to detect an 816. Returns
;
; - carry clear and 0 in A for a NMOS 6502 CPU
; - carry set and 1 in A for some CMOS 6502 CPU
; - carry set and 1 in A for a 65c02
; - carry set and 2 in A for a 65816
; - carry set and 3 in A for a 4510
; - carry set and 4 in A for a 65sc02
; - carry set and 5 in A for a 65ce02
;
; This function uses a $1A opcode which is a INA on the 816 and ignored
; (interpreted as a NOP) on a NMOS 6502. There are several CMOS versions
@ -27,20 +29,40 @@ _getcpu:
cmp #1
bcc @L9
; This is at least a 65C02, check for a 4510
; This is at least a 65C02, check for a 65ce02/4510
.byte $42,$ea ; neg on 4510, nop #$ea on 65c02, wdm $ea on 65816
.byte $42,$ea ; neg on 65ce02/4510, nop #$ea on 65c02, wdm $ea on 65816
cmp #1
bne @L8
beq @L6
; check for 4510
lda #5 ; CPU_65CE02 constant
.byte $5c ; map on 4510, aug on 65ce02 (acts like 4 byte nop)
lda #3 ; CPU_4510 constant
nop
bne @L9
; check for 65sc02
@L6: ldy $f7
ldx #$00
stx $f7
.byte $f7,$f7 ; nop nop on 65sc02, smb7 $f7 on 65c02 and 65816
ldx $f7
sty $f7
cpx #$00
bne @L7
lda #4 ; CPU_65SC02 constant
bne @L9
; check for 65816; after 4510, because $eb there is row (rotate word)
xba ; .byte $eb, put $01 in B accu
@L7: xba ; .byte $eb, put $01 in B accu
dec a ; .byte $3a, A=$00 if 65C02
xba ; .byte $eb, get $01 back if 65816
inc a ; .byte $1a, make $01/$02
.byte $2c ; bit instruction to skip next command
@L8: lda #3 ; CPU_4510 constant
@L9: ldx #0 ; Load high byte of word
rts