From 57a3af36e58bdfb0d082077e0d2ebe799b54adec Mon Sep 17 00:00:00 2001 From: Dmitry Shechtman Date: Tue, 12 Aug 2025 16:25:53 +0300 Subject: [PATCH 1/5] Add BOOTUP_B_DMG0 --- hardware.inc | 3 +++ 1 file changed, 3 insertions(+) diff --git a/hardware.inc b/hardware.inc index e1e3b2c..2c7fa6c 100644 --- a/hardware.inc +++ b/hardware.inc @@ -1037,6 +1037,9 @@ def BOOTUP_A_MGB equ $FF def BOOTUP_A_SGB equ BOOTUP_A_DMG def BOOTUP_A_SGB2 equ BOOTUP_A_MGB +; Register B = CPU qualifier +def BOOTUP_B_DMG0 equ $FF + ; Register B = CPU qualifier (if A is BOOTUP_A_CGB) def B_BOOTUP_B_AGB equ 0 def BOOTUP_B_CGB equ 0 << B_BOOTUP_B_AGB From 8c9d6cda8598fc7f1b799f0bd89d72992463ec92 Mon Sep 17 00:00:00 2001 From: Dmitry Shechtman Date: Tue, 12 Aug 2025 16:37:06 +0300 Subject: [PATCH 2/5] Remove BOOTUP_B_CGB and BOOTUP_B_AGB --- hardware.inc | 2 -- 1 file changed, 2 deletions(-) diff --git a/hardware.inc b/hardware.inc index e1e3b2c..a722087 100644 --- a/hardware.inc +++ b/hardware.inc @@ -1039,8 +1039,6 @@ def BOOTUP_A_MGB equ $FF ; Register B = CPU qualifier (if A is BOOTUP_A_CGB) def B_BOOTUP_B_AGB equ 0 - def BOOTUP_B_CGB equ 0 << B_BOOTUP_B_AGB - def BOOTUP_B_AGB equ 1 << B_BOOTUP_B_AGB ; Register C = CPU qualifier def BOOTUP_C_DMG equ $13 From f4378563fa4fd20a5134ff40cffa7f4b9fb2f48d Mon Sep 17 00:00:00 2001 From: Dmitry Shechtman Date: Tue, 12 Aug 2025 23:22:54 +0300 Subject: [PATCH 3/5] Group boot-up B values --- hardware.inc | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/hardware.inc b/hardware.inc index 79d90a7..ef53f34 100644 --- a/hardware.inc +++ b/hardware.inc @@ -1038,9 +1038,7 @@ def BOOTUP_A_MGB equ $FF def BOOTUP_A_SGB2 equ BOOTUP_A_MGB ; Register B = CPU qualifier -def BOOTUP_B_DMG0 equ $FF - -; Register B = CPU qualifier (if A is BOOTUP_A_CGB) +def BOOTUP_B_DMG0 equ $FF def B_BOOTUP_B_AGB equ 0 ; Register C = CPU qualifier From 36b77b26a049f09e243cec98d498c39127ba1abe Mon Sep 17 00:00:00 2001 From: Dmitry Shechtman Date: Wed, 13 Aug 2025 00:00:20 +0300 Subject: [PATCH 4/5] Add BOOTUP_B_* to hardware_compat.inc --- hardware_compat.inc | 3 +++ 1 file changed, 3 insertions(+) diff --git a/hardware_compat.inc b/hardware_compat.inc index 704777d..9ecceeb 100644 --- a/hardware_compat.inc +++ b/hardware_compat.inc @@ -385,6 +385,9 @@ def OAM_B equ OAM_SIZE def BOOTUPB_B_AGB equ B_BOOTUP_B_AGB + def BOOTUP_B_CGB equ 0 << B_BOOTUP_B_AGB + def BOOTUP_B_AGB equ 1 << B_BOOTUP_B_AGB + ;****************************************************************************** ; Aliases From debac991651131f530c288e069257fed5cc65911 Mon Sep 17 00:00:00 2001 From: Dmitry Shechtman Date: Wed, 13 Aug 2025 15:19:58 +0300 Subject: [PATCH 5/5] Add explanation for BOOTUP_B_* removal --- hardware_compat.inc | 2 ++ 1 file changed, 2 insertions(+) diff --git a/hardware_compat.inc b/hardware_compat.inc index 9ecceeb..e89c523 100644 --- a/hardware_compat.inc +++ b/hardware_compat.inc @@ -385,6 +385,8 @@ def OAM_B equ OAM_SIZE def BOOTUPB_B_AGB equ B_BOOTUP_B_AGB +; These values should not be relied upon; see +; https://gbdev.io/pandocs/Power_Up_Sequence.html#cgbdmg_b def BOOTUP_B_CGB equ 0 << B_BOOTUP_B_AGB def BOOTUP_B_AGB equ 1 << B_BOOTUP_B_AGB