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changeset 2481:f0645adddf0d

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Implement some flow control instructions in new 68K core. WIP implementation of movem in new 68K core.
author Michael Pavone <pavone@retrodev.com>
date Sat, 30 Mar 2024 14:27:47 -0700
parents 369a52e302e2
children fb8f49b0aece
files m68k.cpu
diffstat 1 files changed, 109 insertions(+), 3 deletions(-) [+]
line wrap: on
line diff
--- a/m68k.cpu	Sat Mar 30 14:26:48 2024 -0700
+++ b/m68k.cpu	Sat Mar 30 14:27:47 2024 -0700
@@ -71,9 +71,7 @@
 	and 0x20 status tmp
 	if tmp
 	else
-	
-	xchg other_sp a7
-	
+		xchg other_sp a7
 	end
 	
 m68k_get_sr
@@ -1218,6 +1216,7 @@
 	invalid M 7 R 5
 	invalid M 7 R 6
 	invalid M 7 R 7
+	#TODO: privilege violation exception if in user mode
 	m68k_fetch_src_ea M R 1
 	mov scratch1 ccr
 	lsr scratch1 8 status
@@ -1846,3 +1845,110 @@
 
 0100111001110001 nop
 	m68k_prefetch
+
+0100111001110011 rte
+	#TODO: privilege violation exception if in user mode
+	#Read saved SR
+	scratch1 = a7
+	ocall read_16
+	a7 += 2
+	ccr = scratch1
+	status = scratch1 >> 8
+	#Read saved PC
+	scratch1 = a7
+	m68k_read32
+	a7 += 4
+	pc = scratch1
+	
+	check_user_mode_swap_ssp_usp
+	cycles 4
+	update_sync
+	m68k_prefetch
+
+0100111001110101 m68k_rts
+	scratch1 = a7
+	m68k_read32
+	a7 += 4
+	pc = scratch1
+	
+	cycles 4
+	m68k_prefetch
+
+0100111001110111 rtr
+	#Read saved CCR
+	scratch1 = a7
+	ocall read_16
+	a7 += 2
+	ccr = scratch1
+	#Read saved PC
+	scratch1 = a7
+	m68k_read32
+	a7 += 4
+	pc = scratch1
+	
+	cycles 4
+	m68k_prefetch
+
+0100111010MMMRRR jsr
+	invalid M 0
+	invalid M 1
+	invalid M 3
+	invalid M 4
+	invalid M 7 R 4
+	invalid M 7 R 5
+	invalid M 7 R 6
+	invalid M 7 R 7
+	
+	a7 -= 4
+	scratch1 = a7
+	m68k_write32 pc
+	
+	m68k_calc_ea M R
+	pc = ea
+	
+	cycles 4
+	m68k_prefetch
+
+0100111010MMMRRR jmp
+	invalid M 0
+	invalid M 1
+	invalid M 3
+	invalid M 4
+	invalid M 7 R 4
+	invalid M 7 R 5
+	invalid M 7 R 6
+	invalid M 7 R 7
+	
+	m68k_calc_ea M R
+	pc = ea
+	
+	cycles 4
+	m68k_prefetch
+
+010010001ZMMMRRR movem_reg_to_mem
+	invalid M 0
+	invalid M 1
+	invalid M 3
+	invalid M 7 R 2
+	invalid M 7 R 3
+	invalid M 7 R 4
+	invalid M 7 R 5
+	invalid M 7 R 6
+	invalid M 7 R 7
+	local reglist 16
+	
+	m68k_prefetch
+	reglist = scratch1
+	
+010011001ZMMMRRR movem_mem_to_reg
+	invalid M 0
+	invalid M 1
+	invalid M 4
+	invalid M 7 R 4
+	invalid M 7 R 5
+	invalid M 7 R 6
+	invalid M 7 R 7
+	local reglist 16
+	
+	m68k_prefetch
+	reglist = scratch1