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transfer only 16 bits at a time

This commit is contained in:
Kartik K. Agaram 2021-03-22 23:55:28 -07:00
parent e1843988a4
commit bc79a190ec
1 changed files with 3 additions and 8 deletions
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11
boot.subx
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@ -946,19 +946,14 @@ load-first-sector-from-primary-bus-secondary-drive: # out: (addr stream byte)
(while-ata-busy)
(until-ata-data-available)
# emit results
31/xor %eax 0/r32/eax
ba/copy-to-edx 0x1f0/imm32
b9/copy-to-ecx 0x200/imm32 # 512 bytes per sector
{
81 7/subop/compare %ecx 0/imm32
74/jump-if-= break/disp8
ed/read-port-dx-into-eax
# write 4 bytes to stream one at a time
(append-byte *(ebp+8) %eax)
49/decrement-ecx
c1/shift 5/subop/right-padding-zeroes %eax 8/imm8
(append-byte *(ebp+8) %eax)
49/decrement-ecx
c1/shift 5/subop/right-padding-zeroes %eax 8/imm8
66 ed/read-port-dx-into-ax
# write 2 bytes to stream one at a time
(append-byte *(ebp+8) %eax)
49/decrement-ecx
c1/shift 5/subop/right-padding-zeroes %eax 8/imm8